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Sample records for acid-base equilibrium

  1. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers

    Nap, R. J.; Tagliazucchi, M.; Szleifer, I., E-mail: igalsz@northwestern.edu [Department of Biomedical Engineering, Department of Chemistry, and Chemistry of Life Processes Institute, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3100 (United States)

    2014-01-14

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads

  2. Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers

    Nap, R. J.; Tagliazucchi, M.; Szleifer, I.

    2014-01-01

    This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads

  3. A biochemical model for characterising the surface-active phospolipid bilayer of articular cartilage relative to acid-base equilibrium

    Z. Pawlak; J. Kotynska; Figaszewski, Z A; A. Gadomski; A. Gudaniec; A. Oloyede

    2008-01-01

    Purpose: This paper, addresses the question of how changes in acid - base equilibrium influence change in thecharge density of the phospholipid bilayer on articular cartilage surfaces during lubrication.Design/methodology/approach: Liposomes have been used to mimic biological phospholipid membranes onarticular cartilage surface where proteins are bounded, ions are transported, energy is transducted, and cellular processestake place. The charge density of the membrane was determined as a funct...

  4. Conjugate Acid-Base Pairs, Free Energy, and the Equilibrium Constant

    Beach, Darrell H.

    1969-01-01

    Describes a method of calculating the equilibrium constant from free energy data. Values of the equilibrium constants of six Bronsted-Lowry reactions calculated by the author's method and by a conventional textbook method are compared. (LC)

  5. A biochemical model for characterising the surface-active phospolipid bilayer of articular cartilage relative to acid-base equilibrium

    Z. Pawlak

    2008-01-01

    Full Text Available Purpose: This paper, addresses the question of how changes in acid - base equilibrium influence change in thecharge density of the phospholipid bilayer on articular cartilage surfaces during lubrication.Design/methodology/approach: Liposomes have been used to mimic biological phospholipid membranes onarticular cartilage surface where proteins are bounded, ions are transported, energy is transducted, and cellular processestake place. The charge density of the membrane was determined as a function of pH and electrolyte concentration fromthe microelectrophoretic method. Liposome membrane was prepared as an aqueous solution of NaCl under variouspH conditions. Microelectrophoresis was used to examine the local acid-base equilibrium of the electrolytes with themembrane surface, which can be considered to model the phospholipids interface in articular cartilage.Findings: The adsorbed ions (H+, OH-, Na+, Cl- which are present in the electrically charged solutions of liposomemembrane comprising phosphatidycholine (PC, were found to exhibit pH-responsive quasi-periodic behavior.Research limitations/implications: We have established that the acid-base dissociation behavior inphospholipid bilayers of articular cartilage is a key to understanding biolubrication processes. For example,previous investigators found that the formation of the multilayer of polyisopeptide/hyaluronic acid depends onsurface properties such as film thickness, surface friction, surface wetability; wetness and swelling behavior.Future work should consider the adsorption of polyelectrolyte ions, e.g., the glycoprotein lubricin and hyaluronan,on the liposome membrane surface in the presence of H+ and OH- ions.Originality/value: A novel model of the joints’ phospholipid bilayers has been created using liposome membraneThis model can be applied in the investigation of polyelectrolyte ions such as lubricin, in articular cartilage. Wehave demonstrated that the acid-base processes on

  6. [Materno-fetal acid-base equilibrium evaluation in parturients submitted to ketamine anesthesia (author's transl)].

    Mauad Filho, F; Meirelles, R S

    1975-01-01

    In the present work ketamine was used as anesthetic during the labor in order to evaluate the effect of this anesthetic on the binominal fetus-mother. Two groups of parturients and their fetuses, were studied: 1) The experimental group, with 22 parturients and their fetuses submitted to ketamine anesthesia during the labord, and 2) The control group, with 20 parturients and their fetuses without any analgesic treatment during the labor. In 20 cases of the experimental group the anesthetic was injected during the delivery labor and the other two just before it. It were evaluated in the mother's blood the biochemical parameters of the acid-base balance and others collateral effects of the anesthesia; on the fetus's side the same parameters also and the cardiac frequency. The newborn were evaluated by Apgar Score during the first and fifth minutes of life. The incidence of the spontaneous delivery in the experimental group, was 78%; in 22% of these patients the forceps of relief was used. In 22 cases in which Ketamine was applied it were observed, the following events: elevation of the blood pressure (50%), perineum rigidness (18%), dreams and or hallucinations (18%), increase of the cardiac frequency (9%), apneia (4%) and nausea (4%). It was also observed an increase of uterine tonus an abolishment of abdominal press during the delivery labor, studied through the uterine electromyography register. It was noted after the Ketamine application a fall in the pH of the maternal peripherical venous blood, fetal skull blood and the pH of the blood of the umbilical vein. 22% of the newborns, from the experimental group, presented a depression in the first minute of life (Apgar less than or equals to 6). The pCO2 values in the blood of the umbilical artery were higher in the experimental group than in the control one. PMID:1241148

  7. Acid-base equilibrium during capnoretroperitoneoscopic nephrectomy in patients with end-stage renal failure: a preliminary report.

    Demian, A D; Esmail, O M; Atallah, M M

    2000-04-01

    We have studied the acid-base equilibrium in 12 patients with end-stage renal failure (ESRF) during capnoretroperitoneoscopic nephrectomy. Bupivacaine (12 mL, 0.375%) and morphine (2mg) were given in the lumbar epidural space, and fentanyl (0.5 microg kg(-1)) and midazolam (50 microg kg(-1)) were given intravenously. Anaesthesia was induced by thiopental, maintained with halothane carried by oxygen enriched air (inspired oxygen fraction = 0.35), and ventilation was achieved with a tidal volume of 10 mL kg(-1) at a rate of 12 min(-1). This procedure resulted in a mild degree of respiratory acidosis that was cleared within 60 min. We conclude that capnoretroperitoneoscopic nephrectomy can be performed in patients with end-stage renal failure with minimal transient respiratory acidosis that can be avoided by increased ventilation. PMID:10866009

  8. Acid-base equilibrium in aqueous solutions of 1,3-dimethylbarbituric acid as studied by 13C NMR spectroscopy

    Gryff-Keller, A.; Kraska-Dziadecka, A.

    2011-12-01

    13C NMR spectra of 1,3-dimethylbarbituric acid in aqueous solutions of various acidities and for various solute concentrations have been recorded and interpreted. The spectra recorded at pH = 2 and below contain the signals of the neutral solute molecule exclusively, while the ones recorded at pH = 7 and above only the signals of the appropriate anion, which has been confirmed by theoretical GIAO-DFT calculations. The signals in the spectra recorded for solutions of pH acid-base equilibrium. The kinetic data determined this way have been used to clarify the mechanisms of these processes. The numerical analysis has shown that under the investigated conditions deprotonation of the neutral solute molecules undergoes not only via a simple transfer of the C-H proton to water molecules but also through a process with participation of the barbiturate anions. Moreover, the importance of tautomerism, or association, or both these phenomena for the kinetics of the acid-base transformations in the investigated system has been shown. Qualitatively similar changes of 13C NMR spectra with the solution pH variation have been observed for the parent barbituric acid.

  9. Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity

    Cantu Cantu, David; Lee, Jun Taek; Lee, Mal Soon; Heldebrant, David J.; Koech, Phillip K.; Freeman, Charles J.; Rousseau, Roger J.; Glezakou, Vassiliki Alexandra

    2016-05-05

    The deployment of transformational non-aqueous CO2-capture solvent systems is encumbered by high viscosity even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we identify the key molecular features controlling bulk liquid viscosity and CO2 uptake kinetics. Fast uptake kinetics arise from close proximity of the alcohol and amine sites that are involved in CO2 binding. This process results in the concerted formation of a Zwitterion containing both an alkylcarbonate and a protonated amine. The hydrogen bonding between the two functional groups ultimately determines the solution viscosity. Based on molecular simulation, this work reveals options to significantly reduce viscosity with molecular modifications that shift the proton transfer equilibrium towards a neutral acid/amine species as opposed to the ubiquitously accepted Zwitterionic state. The molecular design concepts proposed here, for the alkyl-carbonate systems, are readily extensible to other CO2 capture technologies, such as the carbamate- or imidazole-based solvent chemistries.

  10. Dynamic Acid/Base Equilibrium in Single Component Switchable Ionic Liquids and Consequences on Viscosity.

    Cantu, David C; Lee, Juntaek; Lee, Mal-Soon; Heldebrant, David J; Koech, Phillip K; Freeman, Charles J; Rousseau, Roger; Glezakou, Vassiliki-Alexandra

    2016-05-01

    The deployment of transformational nonaqueous CO2-capture solvent systems is encumbered by high viscosities even at intermediate uptakes. Using single-molecule CO2 binding organic liquids as a prototypical example, we present key molecular features that control bulk viscosity. Fast CO2-uptake kinetics arise from close proximity of the alcohol and amine sites involved in CO2 binding in a concerted fashion, resulting in a Zwitterion containing both an alkyl-carbonate and a protonated amine. The population of internal hydrogen bonds between the two functional groups determines the solution viscosity. Unlike the ion pair interactions in ionic liquids, these observations are novel and specific to a hydrogen-bonding network that can be controlled by chemically tuning single molecule CO2 capture solvents. We present a molecular design strategy to reduce viscosity by shifting the proton transfer equilibrium toward a neutral acid/amine species, as opposed to the ubiquitously accepted zwitterionic state. The molecular design concepts proposed here are readily extensible to other CO2 capture technologies. PMID:27019342

  11. Lysozyme adsorption in pH-responsive hydrogel thin-films: the non-trivial role of acid-base equilibrium.

    Narambuena, Claudio F; Longo, Gabriel S; Szleifer, Igal

    2015-09-01

    We develop and apply a molecular theory to study the adsorption of lysozyme on weak polyacid hydrogel films. The theory explicitly accounts for the conformation of the network, the structure of the proteins, the size and shape of all the molecular species, their interactions as well as the chemical equilibrium of each titratable unit of both the protein and the polymer network. The driving forces for adsorption are the electrostatic attractions between the negatively charged network and the positively charged protein. The adsorption is a non-monotonic function of the solution pH, with a maximum in the region between pH 8 and 9 depending on the salt concentration of the solution. The non-monotonic adsorption is the result of increasing negative charge of the network with pH, while the positive charge of the protein decreases. At low pH the network is roughly electroneutral, while at sufficiently high pH the protein is negatively charged. Upon adsorption, the acid-base equilibrium of the different amino acids of the protein shifts in a nontrivial fashion that depends critically on the particular kind of residue and solution composition. Thus, the proteins regulate their charge and enhance adsorption under a wide range of conditions. In particular, adsorption is predicted above the protein isoelectric point where both the solution lysozyme and the polymer network are negatively charged. This behavior occurs because the pH in the interior of the gel is significantly lower than that in the bulk solution and it is also regulated by the adsorption of the protein in order to optimize protein-gel interactions. Under high pH conditions we predict that the protein changes its charge from negative in the solution to positive within the gel. The change occurs within a few nanometers at the interface of the hydrogel film. Our predictions show the non-trivial interplay between acid-base equilibrium, physical interactions and molecular organization under nanoconfined conditions

  12. Students' Understanding of Acids/Bases in Organic Chemistry Contexts

    Cartrette, David P.; Mayo, Provi M.

    2011-01-01

    Understanding key foundational principles is vital to learning chemistry across different contexts. One such foundational principle is the acid/base behavior of molecules. In the general chemistry sequence, the Bronsted-Lowry theory is stressed, because it lends itself well to studying equilibrium and kinetics. However, the Lewis theory of…

  13. Physiological roles of acid-base sensors.

    Levin, Lonny R; Buck, Jochen

    2015-01-01

    Acid-base homeostasis is essential for life. The macromolecules upon which living organisms depend are sensitive to pH changes, and physiological systems use the equilibrium between carbon dioxide, bicarbonate, and protons to buffer their pH. Biological processes and environmental insults are constantly challenging an organism's pH; therefore, to maintain a consistent and proper pH, organisms need sensors that measure pH and that elicit appropriate responses. Mammals use multiple sensors for measuring both intracellular and extracellular pH, and although some mammalian pH sensors directly measure protons, it has recently become apparent that many pH-sensing systems measure pH via bicarbonate-sensing soluble adenylyl cyclase. PMID:25340964

  14. 吲哚荷尔蒙自由基脉冲辐解光谱及其酸基平衡和还原电位性质研究%The spectral, acid-base equilibrium and reduction potential properties of indole hormone radicals: a pulse radiolysis study

    H He; M Lin; Z Han; Y Muroya; H Kudo; Y Katsumura; M Iwata

    2005-01-01

    The Absorption spectral, acid-base equilibrium potential properties and formation and decay kinetics of four kinds of radicals from natural existing indole hormones were studied by pulse radiolysis.One of the most important properties for these four indolyl hormones, melatonin, 5-methoxygramine (MTA),5-methoxy-N, N-dimethylthytrytamine (DMM TA) and 5-methoxy-N, N-diethylthytrytamine (DEMT A), which are involved in biochemical processes and play crucial roles in many neuropathy and cancer related diseases, is their facile one electron oxidation with formation of radical cations or their conjugated base, the indolyl radicals.Formation kinetics and properties of the radicals were investigated by pulse radiolysis using the Linac accelerator with fast time-resolving optical system in UTNL.In the present study, these radicals were generated through oxidation of the corresponding hormone with azide radical in radiation induced process. Their spectroscopic properties were investigated and it was found that the transient spectra in all these cases exhibit similar absorption and pH dependence: in acidic solution, the radicals are characterized with three absorption maxima around 320-350, 440-460, 520-550nm. The spectra of MTA at various pH were shown as an example. From the absorption changes as a function of pH, two pK values were determined to be around 5 and 9 for the indolyl radicals except for melatonin, in which, only one pK was distinguished to be 4.4. Formation kinetics of the radicals was measured by following the growth of their absorption peaks and it was found that these indolyl derivatives transfer an electron to N3, with different rate constants, i.e.1.2×1010, 4.5×109, 4.9×109, 1.6×109 dm3 mol-1 s-1 for melatonin, MTA, DMMTA, and DEMTA, respectively.Reduction potentials of the radicals vs their molecules were also determined and they are dependent on the pH of medium. At pH 7, the reduction potentials were estimated to be 1.10, 1.18, 1.18, 1.20eV for

  15. Molten fatty acid based microemulsions.

    Noirjean, Cecile; Testard, Fabienne; Dejugnat, Christophe; Jestin, Jacques; Carriere, David

    2016-06-21

    We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound. PMID:27241163

  16. GENERAL EQUILIBRIUM

    Monique Florenzano

    2008-09-01

    Full Text Available General equilibrium is a central concept of economic theory. Unlike partial equilibrium analysis which study the equilibrium of a particular market under the clause “ceteris paribus” that revenues and prices on the other markets stay approximately unaffected, the ambition of a general equilibrium model is to analyze the simultaneous equilibrium in all markets of a competitive economy. Definition of the abstract model, some of its basic results and insights are presented. The important issues of uniqueness and local uniqueness of equilibrium are sketched; they are the condition for a predictive power of the theory and its ability to allow for statics comparisons. Finally, we review the main extensions of the general equilibrium model. Besides the natural extensions to infinitely many commodities and to a continuum of agents, some examples show how economic theory can accommodate the main ideas in order to study some contexts which were not thought of by the initial model

  17. Maximin equilibrium

    Ismail M.S

    2014-01-01

    We introduce a new concept which extends von Neumann and Morgensterns maximin strategy solution by incorporating individual rationality of the players. Maximin equilibrium, extending Nashs value approach, is based on the evaluation of the strategic uncertainty of the whole game. We show that maximin equilibrium is invariant under strictly increasing transformations of the payoffs. Notably, every finite game possesses a maximin equilibrium in pure strategies. Considering the games in von Neuma...

  18. Partition Equilibrium

    Feldman, Michal; Tennenholtz, Moshe

    We introduce partition equilibrium and study its existence in resource selection games (RSG). In partition equilibrium the agents are partitioned into coalitions, and only deviations by the prescribed coalitions are considered. This is in difference to the classical concept of strong equilibrium according to which any subset of the agents may deviate. In resource selection games, each agent selects a resource from a set of resources, and its payoff is an increasing (or non-decreasing) function of the number of agents selecting its resource. While it has been shown that strong equilibrium exists in resource selection games, these games do not possess super-strong equilibrium, in which a fruitful deviation benefits at least one deviator without hurting any other deviator, even in the case of two identical resources with increasing cost functions. Similarly, strong equilibrium does not exist for that restricted two identical resources setting when the game is played repeatedly. We prove that for any given partition there exists a super-strong equilibrium for resource selection games of identical resources with increasing cost functions; we also show similar existence results for a variety of other classes of resource selection games. For the case of repeated games we identify partitions that guarantee the existence of strong equilibrium. Together, our work introduces a natural concept, which turns out to lead to positive and applicable results in one of the basic domains studied in the literature.

  19. Helical equilibrium

    A straight, helical plasma equilibrium equation is solved numerically for a plasma with a helical magnetic axis. As is expected, by a suitable choice of the plasma boundary, the vacuum configuration is made line ∫ dl/B stable. As the plasma pressure increases, the line ∫ dl/B criterion will improve (again as expected). There is apparently no limit on the plasma β from the equilibrium consideration. Thus helical-axis stellarator β will presumably be limited by MHD stability β, and not by equilibrium β

  20. Hypokalemic paralysis and acid-base balance

    Ivo Casagranda

    2006-10-01

    Full Text Available Three cases of hypokalemic paralysis are reported, presenting to the Emergency Department. The first is a patient with a hypokalemic periodic paralysis with a normal acid-base status, the second is a case of hypokalemic flaccid paralysis of all extremities with a normal anion gap metabolic acidosis, the last is a patient with a hypokalemic distal paralysis of right upper arm with metabolic alkalosis. Afterwards some pathophysiologic principles and the clinical aspects of hypokalemia are discussed and an appropriate approach to do in Emergency Department, to identify the hypokalemic paralysis etiologies in the Emergency Department, is presented, beginning from the evaluation of acid-base status.

  1. Jigsaw Cooperative Learning: Acid-Base Theories

    Tarhan, Leman; Sesen, Burcin Acar

    2012-01-01

    This study focused on investigating the effectiveness of jigsaw cooperative learning instruction on first-year undergraduates' understanding of acid-base theories. Undergraduates' opinions about jigsaw cooperative learning instruction were also investigated. The participants of this study were 38 first-year undergraduates in chemistry education…

  2. Hypokalemic paralysis and acid-base balance

    Ivo Casagranda; Riccardo Boverio; Andrea Defrancisci; Sara Ferrillo; Francesca Gargiulo

    2006-01-01

    Three cases of hypokalemic paralysis are reported, presenting to the Emergency Department. The first is a patient with a hypokalemic periodic paralysis with a normal acid-base status, the second is a case of hypokalemic flaccid paralysis of all extremities with a normal anion gap metabolic acidosis, the last is a patient with a hypokalemic distal paralysis of right upper arm with metabolic alkalosis. Afterwards some pathophysiologic principles and the clinical aspects of hypokalemia are discu...

  3. Sweatshop equilibrium

    Chau, Nancy H.

    2009-01-01

    This paper presents a capability-augmented model of on the job search, in which sweatshop conditions stifle the capability of the working poor to search for a job while on the job. The augmented setting unveils a sweatshop equilibrium in an otherwise archetypal Burdett-Mortensen economy, and reconciles a number of oft noted yet perplexing features of sweatshop economies. We demonstrate existence of multiple rational expectation equilibria, graduation pathways out of sweatshops in complete abs...

  4. Nicotinic and iso nicotinic acids: interactions with gamma radiation and acid-base equilibrium

    The values of pKa1 and pKa2 for nicotinic and iso nicotinic acids in aqueous medium were determined. The effects of gamma radiation about these acids by infrared and ultraviolet spectrophotometry and thermal gravimetric analysis were also studied. It was verified that the radiolysis of acids occurred by the two process of first order, determining the degradation constant and the degradation factors for each one of the solutions. (C.G.C.)

  5. ACID-BASE INTERACTIONS BETWEEN POLYMERS AND FILLERS

    WANG Qingguo; CHEN Fute; HUANG Yuanfu; ZHOU Qingli

    1987-01-01

    Inverse gas chromatography(IGC) and Fourier-transform infrared (FT-IR) techniques were applied to determining the relative acid-base strength of polymers and coupling agents. The acid-base characteristics of fillers such as CaCO3 could be altered by treatment with different coupling agents. It was shown that some mechanical properties of filled polymers were obviously associated with acid-base interactions between polymers and fillers.

  6. Robust Learning Equilibrium

    Ashlagi, Itai; Monderer, Dov; Tennenholtz, Moshe

    2012-01-01

    We introduce robust learning equilibrium. The idea of learning equilibrium is that learning algorithms in multi-agent systems should themselves be in equilibrium rather than only lead to equilibrium. That is, learning equilibrium is immune to strategic deviations: Every agent is better off using its prescribed learning algorithm, if all other agents follow their algorithms, regardless of the unknown state of the environment. However, a learning equilibrium may not be immune to non strategic m...

  7. "Equilibrium" states of non equilibrium system

    Lev, Bohdan

    2008-01-01

    A possible approach to description of the non equilibrium system has been proposed. Based on the Fokker-Plank equation in term of energy for non equilibrium distribution function of macroscopical system was obtained the stationary solution which can be interpreted as the equilibrium distribution function for new energetic state. The proposed approach takes into account the possible motion between different states of system, induced by dissipation of energy and influence of environment which d...

  8. Boronic acid-based autoligation of nucleic acids

    Barbeyron, R.; Vasseur, J.-J.; Smietana, M.;

    2013-01-01

    Abstract: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible...

  9. Teaching acid/base physiology in the laboratory

    Friis, Ulla G; Plovsing, Ronni; Hansen, Klaus;

    2010-01-01

    Acid/base homeostasis is one of the most difficult subdisciplines of physiology for medical students to master. A different approach, where theory and practice are linked, might help students develop a deeper understanding of acid/base homeostasis. We therefore set out to develop a laboratory...... exercise in acid/base physiology that would provide students with unambiguous and reproducible data that clearly would illustrate the theory in practice. The laboratory exercise was developed to include both metabolic acidosis and respiratory alkalosis. Data were collected from 56 groups of medical...... students that had participated in this laboratory exercise. The acquired data showed very consistent and solid findings after the development of both metabolic acidosis and respiratory alkalosis. All results were consistent with the appropriate diagnosis of the acid/base disorder. Not one single group...

  10. Acid-base homeostasis in the human system

    White, R. J.

    1974-01-01

    Acid-base regulation is a cooperative phenomena in vivo with body fluids, extracellular and intracellular buffers, lungs, and kidneys all playing important roles. The present account is much too brief to be considered a review of present knowledge of these regulatory systems, and should be viewed, instead, as a guide to the elements necessary to construct a simple model of the mutual interactions of the acid-base regulatory systems of the body.

  11. Pattern of acid base abnormalities in critically ill patinets

    To find out the pattern of acid base abnormalities in critically ill patients in a tertiary care health facility. Study Design: A descriptive study. Place and Duration of Study: The study was carried out in the department of pathology, Combined Military Hospital Kharian from January 2013 to June 2013. Patients and Methods: Two hundred and fifty patients suffering from various diseases and presenting with exacerbation of their clinical conditions were studied. These patients were hospitalized and managed in acute care units of the hospital. Arterial blood gases were analysed to detect acid base status and their correlation with their clinical condition. Concomitant analysis of electrolytes was carried out. Tests related to concurrent illnesses e.g. renal and liver function tests, cardiac enzymes and plasma glucose were assayed by routine end point and kinetic methods. Standard reference materials were used to ensure internal quantify control of analyses. Results: Two hundred and fifteen patients out of 250 studied suffered from acid base disorders. Gender distribution showed a higher percentage of male patients and the mean age was 70.5 ± 17.4 years. Double acid base disorders were the commonest disorders (34%) followed by metabolic acidosis (30%). Anion gap was calculated to further stratify metabolic acidosis and cases of diabetic ketoacidosis were the commonest in this category (47%). Other simple acid base disorders were relatively less frequent. Delta bicarbonate was calculated to unmask the superimposition of respiratory alkalosis or acidosis with metabolic acidosis and metabolic alkalosis. Though triple acid base disorders were noted in a small percentage of cases (05%), but were found to be the most complicated and challenging. Mixed acid base disorders were associated with high mortality. Conclusion: A large number of critically ill patients manifested acid base abnormalities over the full spectrum of these disorders. Mixed acid base disorders were

  12. Ion equilibrium in the solutions of ethynil piperidol polymers and pectin substances, synthesis, inter polyelectrolyte complexes on their bases

    Present article is devoted to ion equilibrium in the solutions of ethynil piperidol polymers and pectin substances, synthesis, inter polyelectrolyte complexes on their bases. Thus, the ion equilibrium in the solutions of ethynyl vinyl trimethyl piperidine and its derivatives is studied. Acid-base equilibrium in aqueous solutions of pectin substances is considered. Ion equilibrium in aqueous solutions of pectin substances is studied as well.

  13. Ion exchange equilibrium constants

    Marcus, Y

    2013-01-01

    Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

  14. Acids and bases solvent effects on acid-base strenght

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  15. Enhanced Acid/Base Catalysis in High Temperature Liquid Water

    Xiu Yang LU; Qi JING; Zhun LI; Lei YUAN; Fei GAO; Xin LIU

    2006-01-01

    Two novel and environmentally benign solvent systems, organic acids-enriched high temperature liquid water (HTLW) and NH3-enriched HTLW, were developed, which can enhance the reaction rate of acid/base-catalyzed organic reactions in HTLW. We investigated the decomposition of fructose in organic acids-enriched HTLW, hydrolysis of cinnamaldehyde and aldol condensation of phenylaldehyde with acetaldehyde in NH3-enriched HTLW. The experimental results demonstrated that organic acids-enriched or NH3-enriched HTLW can greatly accelerate acid/base-catalyzed organic reactions in HTLW.

  16. Acid-base disturbance in patients with cirrhosis

    Henriksen, Jens H; Bendtsen, Flemming; Møller, Søren

    2015-01-01

    PURPOSE: Acid-base disturbances were investigated in patients with cirrhosis in relation to hemodynamic derangement to analyze the hyperventilatory effects and the metabolic compensation. METHODS: A total of 66 patients with cirrhosis and 44 controls were investigated during a hemodynamic study......, and effects of unidentified ions (all Pacid-base disturbances could not be identified. CONCLUSION: Hypocapnic alkalosis is related to disease severity and hyperdynamic systemic circulation in patients with cirrhosis. The metabolic compensation includes...... alterations in serum albumin and water retention that may result in a delicate acid-base balance in these patients....

  17. ON VECTOR NETWORK EQUILIBRIUM PROBLEMS

    Guangya CHEN

    2005-01-01

    In this paper we define a concept of weak equilibrium for vector network equilibrium problems.We obtain sufficient conditions of weak equilibrium points and establish relation with vector network equilibrium problems and vector variational inequalities.

  18. Phase equilibrium engineering

    Brignole, Esteban Alberto

    2013-01-01

    Traditionally, the teaching of phase equilibria emphasizes the relationships between the thermodynamic variables of each phase in equilibrium rather than its engineering applications. This book changes the focus from the use of thermodynamics relationships to compute phase equilibria to the design and control of the phase conditions that a process needs. Phase Equilibrium Engineering presents a systematic study and application of phase equilibrium tools to the development of chemical processes. The thermodynamic modeling of mixtures for process development, synthesis, simulation, design and

  19. Equilibrium and generators

    This work studies the behaviour of radionuclides when it produce a desintegration activity,decay and the isotopes stable creation. It gives definitions about the equilibrium between activity of parent and activity of the daughter, radioactive decay,isotope stable and transient equilibrium and maxim activity time. Some considerations had been given to generators that permit a disgregation of two radioisotopes in equilibrium and its good performance. Tabs

  20. Soil Studies: Applying Acid-Base Chemistry to Environmental Analysis.

    West, Donna M.; Sterling, Donna R.

    2001-01-01

    Laboratory activities for chemistry students focus attention on the use of acid-base chemistry to examine environmental conditions. After using standard laboratory procedures to analyze soil and rainwater samples, students use web-based resources to interpret their findings. Uses CBL probes and graphing calculators to gather and analyze data and…

  1. Acid-base transport in pancreas-new challenges

    Novak, Ivana; Haanes, Kristian Agmund; Wang, Jing

    2013-01-01

    to consider in pancreas are the proton pumps (H-K-ATPases), as well as the calcium-activated K and Cl channels, such as K3.1 and TMEM16A/ANO1. Local regulators, such as purinergic signaling, fine-tune, and coordinate pancreatic secretion. Lastly, we speculate whether dys-regulation of acid-base transport...

  2. Acid-base behavior in hydrothermal processing of wastes. 1997 annual progress report

    'A major obstacle to the development of hydrothermal technology for treating DOE wastes has been a lack of scientific knowledge of solution chemistry, thermodynamics and transport phenomena. The progress over the last year is highlighted in the following four abstracts from manuscripts which have been submitted to journals. The authors also have made considerable progress on a spectroscopic study of the acid-base equilibria of Cr(VI). They have utilized novel spectroscopic indicators to study acid-base equilibria up to 380 C. Until now, very few systems have been studied at such high temperatures, although this information is vital for hydrothermal processing of wastes. The pH values of aqueous solutions of boric acid and KOH were measured with the optical indicator 2-naphthol at temperatures from 300 to 380 C. The equilibrium constant Kb-l for the reaction B(OH)3 + OH- = B(OH)-4 was determined from the pH measurements and correlated with a modified Born model. The titration curve for the addition of HCl to sodium borate exhibits strong acid-strong base behavior even at 350 C and 24.1 MPa. At these conditions, aqueous solutions of sodium borate buffer the pH at 9.6 t 0.25. submitted to Ind. Eng. Chem. Res. Acetic Acid and HCl Acid-base titrations for the KOH-acetic acid or NH3 -acetic acid systems were monitored with the optical indicator 2-naphthoic acid at 350 C and 34 MPa, and those for the HCl;Cl- system with acridine at 380 C and up to 34 MPa (5,000 psia ). KOH remains a much stronger base than NH,OH at high temperature. From 298 K to the critical temperature of water, the dissociation constant for HCl decreases by 13 orders of magnitude, and thus, the basicity of Cl- becomes significant. Consequently, the addition of NaCl to HCl raises the pH. The pH titration curves may be predicted with reasonable accuracy from the relevant equilibrium constants and Pitzer''s formulation of the Debye- Htickel equation for the activity coefficients.'

  3. Seawater salinity and blood acid-base balance in the lugworm, Arenicola marina (L.).

    Toulmond, A; Jouin, C

    1992-03-01

    The kinetics of variations in the blood acid base balance (ABB) were investigated in a moderately euryhaline osmoconformer, the lugworm Arenicola marina (L.), exposed to natural and experimental hypo- or hyperosmotic shocks. In natural as well as in experimental conditions, a hyposmotic shock induced a transient and essentially metabolic acidosis, probably linked to the ionic readjustments following the shock, which was rapidly overridden by a metabolic alkalosis. In field conditions, a new ABB equilibrium was then attained, the metabolic alkalosis being neutralized by the respiratory and metabolic acidosis occurring normally in the lugworm during low tide. Conversely, in the normoxic conditions of our laboratory experiments, a new ABB equilibrium was never reached. Under experimental conditions, a hyperosmotic shock always induced a respiratory and metabolic acidosis. In the field, this phenomenon must occur at the beginning of high tide and must help to restore normal blood ABB in lugworms submitted to a moderate hyposmotic shock during low tide. All the observed blood ABB variations reveal the complex intracellular processes through which the lugworm submitted to moderate osmotic shocks tentatively regulates, sometimes without any real success, its osmoticity and volume. Obviously, complementary physical, physiological and behavioral mechanisms allow the lugworm to live in sediments washed by almost fresh water during a 7-8 h 'low tide'. PMID:1604064

  4. Nucleic acid-based approaches to STAT inhibition.

    Sen, Malabika; Grandis, Jennifer R

    2012-10-01

    Silencing of abnormally activated genes can be accomplished in a highly specific manner using nucleic acid based approaches. The focus of this review includes the different nucleic acid based inhibition strategies such as antisense oligodeoxynucleotides, small interfering RNA (siRNA), dominant-negative constructs, G-quartet oligonucleotides and decoy oligonucleotides, their mechanism of action and the effectiveness of these approaches to targeting the STAT (signal transducer and activator of transcription) proteins in cancer. Among the STAT proteins, especially STAT3, followed by STAT5, are the most frequently activated oncogenic STATs, which have emerged as plausible therapeutic cancer targets. Both STAT3 and STAT5 have been shown to regulate numerous oncogenic signaling pathways including proliferation, survival, angiogenesis and migration/invasion. PMID:24058785

  5. Nucleic Acid-Based Nanodevices in Biological Imaging.

    Chakraborty, Kasturi; Veetil, Aneesh T; Jaffrey, Samie R; Krishnan, Yamuna

    2016-06-01

    The nanoscale engineering of nucleic acids has led to exciting molecular technologies for high-end biological imaging. The predictable base pairing, high programmability, and superior new chemical and biological methods used to access nucleic acids with diverse lengths and in high purity, coupled with computational tools for their design, have allowed the creation of a stunning diversity of nucleic acid-based nanodevices. Given their biological origin, such synthetic devices have a tremendous capacity to interface with the biological world, and this capacity lies at the heart of several nucleic acid-based technologies that are finding applications in biological systems. We discuss these diverse applications and emphasize the advantage, in terms of physicochemical properties, that the nucleic acid scaffold brings to these contexts. As our ability to engineer this versatile scaffold increases, its applications in structural, cellular, and organismal biology are clearly poised to massively expand. PMID:27294440

  6. Carbonic anhydrase 5 regulates acid-base homeostasis in zebrafish.

    Ruben Postel

    Full Text Available The regulation of the acid-base balance in cells is essential for proper cellular homeostasis. Disturbed acid-base balance directly affects cellular physiology, which often results in various pathological conditions. In every living organism, the protein family of carbonic anhydrases regulate a broad variety of homeostatic processes. Here we describe the identification, mapping and cloning of a zebrafish carbonic anhydrase 5 (ca5 mutation, collapse of fins (cof, which causes initially a collapse of the medial fins followed by necrosis and rapid degeneration of the embryo. These phenotypical characteristics can be mimicked in wild-type embryos by acetazolamide treatment, suggesting that CA5 activity in zebrafish is essential for a proper development. In addition we show that CA5 regulates acid-base balance during embryonic development, since lowering the pH can compensate for the loss of CA5 activity. Identification of selective modulators of CA5 activity could have a major impact on the development of new therapeutics involved in the treatment of a variety of disorders.

  7. DIAGNOSIS OF FINANCIAL EQUILIBRIUM

    SUCIU GHEORGHE

    2013-04-01

    Full Text Available The analysis based on the balance sheet tries to identify the state of equilibrium (disequilibrium that exists in a company. The easiest way to determine the state of equilibrium is by looking at the balance sheet and at the information it offers. Because in the balance sheet there are elements that do not reflect their real value, the one established on the market, they must be readjusted, and those elements which are not related to the ordinary operating activities must be eliminated. The diagnosis of financial equilibrium takes into account 2 components: financing sources (ownership equity, loaned, temporarily attracted. An efficient financial equilibrium must respect 2 fundamental requirements: permanent sources represented by ownership equity and loans for more than 1 year should finance permanent needs, and temporary resources should finance the operating cycle.

  8. Non-equilibrium Economics

    Katalin Martinás

    2007-02-01

    Full Text Available A microeconomic, agent based framework to dynamic economics is formulated in a materialist approach. An axiomatic foundation of a non-equilibrium microeconomics is outlined. Economic activity is modelled as transformation and transport of commodities (materials owned by the agents. Rate of transformations (production intensity, and the rate of transport (trade are defined by the agents. Economic decision rules are derived from the observed economic behaviour. The non-linear equations are solved numerically for a model economy. Numerical solutions for simple model economies suggest that the some of the results of general equilibrium economics are consequences only of the equilibrium hypothesis. We show that perfect competition of selfish agents does not guarantee the stability of economic equilibrium, but cooperativity is needed, too.

  9. Equilibrium statistical mechanics

    Mayer, J E

    1968-01-01

    The International Encyclopedia of Physical Chemistry and Chemical Physics, Volume 1: Equilibrium Statistical Mechanics covers the fundamental principles and the development of theoretical aspects of equilibrium statistical mechanics. Statistical mechanical is the study of the connection between the macroscopic behavior of bulk matter and the microscopic properties of its constituent atoms and molecules. This book contains eight chapters, and begins with a presentation of the master equation used for the calculation of the fundamental thermodynamic functions. The succeeding chapters highlight t

  10. Affine General Equilibrium Models

    Bjørn Eraker

    2008-01-01

    No-arbitrage models are extremely flexible modelling tools but often lack economic motivation. This paper describes an equilibrium consumption-based CAPM framework based on Epstein-Zin preferences, which produces analytic pricing formulas for stocks and bonds under the assumption that macro growth rates follow affine processes. This allows the construction of equilibrium pricing formulas while maintaining the same flexibility of state dynamics as in no-arbitrage models. In demonstrating the a...

  11. Computing Equilibrium Chemical Compositions

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

    Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

  12. Perfect Regular Equilibrium

    hanjoon michael, jung/j

    2010-01-01

    We propose a revised version of the perfect Bayesian equilibrium in general multi-period games with observed actions. In finite games, perfect Bayesian equilibria are weakly consistent and subgame perfect Nash equilibria. In general games that allow a continuum of types and strategies, however, perfect Bayesian equilibria might not satisfy these criteria of rational solution concepts. To solve this problem, we revise the definition of the perfect Bayesian equilibrium by replacing Bayes' rule ...

  13. Developing nucleic acid-based electrical detection systems

    Gabig-Ciminska Magdalena

    2006-03-01

    Full Text Available Abstract Development of nucleic acid-based detection systems is the main focus of many research groups and high technology companies. The enormous work done in this field is particularly due to the broad versatility and variety of these sensing devices. From optical to electrical systems, from label-dependent to label-free approaches, from single to multi-analyte and array formats, this wide range of possibilities makes the research field very diversified and competitive. New challenges and requirements for an ideal detector suitable for nucleic acid analysis include high sensitivity and high specificity protocol that can be completed in a relatively short time offering at the same time low detection limit. Moreover, systems that can be miniaturized and automated present a significant advantage over conventional technology, especially if detection is needed in the field. Electrical system technology for nucleic acid-based detection is an enabling mode for making miniaturized to micro- and nanometer scale bio-monitoring devices via the fusion of modern micro- and nanofabrication technology and molecular biotechnology. The electrical biosensors that rely on the conversion of the Watson-Crick base-pair recognition event into a useful electrical signal are advancing rapidly, and recently are receiving much attention as a valuable tool for microbial pathogen detection. Pathogens may pose a serious threat to humans, animal and plants, thus their detection and analysis is a significant element of public health. Although different conventional methods for detection of pathogenic microorganisms and their toxins exist and are currently being applied, improvements of molecular-based detection methodologies have changed these traditional detection techniques and introduced a new era of rapid, miniaturized and automated electrical chip detection technologies into pathogen identification sector. In this review some developments and current directions in

  14. Advances in nucleic acid-based diagnostics of bacterial infections

    Barken, Kim Bundvig; Haagensen, Janus Anders Juul; Tolker-Nielsen, Tim

    2007-01-01

    Methods for rapid detection of infectious bacteria and antimicrobial-resistant pathogens have evolved significantly over the last decade. Many of the new procedures are nucleic acid-based and replace conventional diagnostic methods like culturing which is time consuming especially with fastidious...... of these pathogens is important to isolate patients and prevent further spreading of the diseases. Newly developed diagnostic procedures are superior with respect to turnaround time, sensitivity and specificity. Methods like multiplex real time PCR and different array-based technologies offer the possibility...

  15. Syntheses and characterizations of three acid-base supramolecular complexes

    Three acid-base compounds with supramolecular architectures, namely, (1,2-H2bdc)(dmt) (1), (trans-1,4-H2ccdc)0.5(phdat) (2) and (1,3-H2bdc)(phdat) (3) (1,2-H2bdc = 1,2-benzenedicarboxylic acid, trans-1, 4-H2ccdc = trans-1, 4-cyclohexanedicarboxylic acid, 1,3-H2bdc = 1,3-benzenedicarboxylic acid, dmt = 2,4-diamino-6-methyl-s-triazine, phdat = 2,4-diamino-6-phenyl-s-triazine) have been synthesized and characterized by IR spectra, elemental analyses, single-crystal X-ray diffractions and TGA. (author)

  16. Determination of nonaxisymmetric equilibrium

    The Princeton Equilibrium Code is modified to determine the equilibrium surfaces for a large aspect ratio toroidal system with helical magnetic fields. The code may easily be made to include any variety of modes. Verification of the code is made by comparison with an analytic solution for l = 3. Previously observed shifting of the magnetic axis with increasing pressure or with a changed externally applied vertical field is obtained. The case l = 0, a bumpy torus, gives convergence only for the lenient convergence tolerance of epsilon/sub b/ = 1.0 x 10-2

  17. Opuntia ficus indica (L.) Fruit Extract as Natural Indicator in Acid-Base Titration

    Manoj A. Suva

    2014-01-01

    In routine experiments synthetic indicators are the choice of acid base titrations. But there are some limitations like environmental pollution, availability and higher cost which leads to search for natural compounds as an acid base indicator was started. The present work highlights theexploit of the methanolic and aqueous extract of the fruit of Opuntia ficus indica plants as a natural acid base indicator in acid base titrations. Opuntia ficus indica plant was identified and fruits were was...

  18. Acid base catalyzed transesterification kinetics of waste cooking oil

    Jain, Siddharth; Sharma, M.P.; Rajvanshi, Shalini [Alternate Hydro Energy Centre, Indian Institute of Technology, Roorkee (India)

    2011-01-15

    The present study reports the results of kinetics study of acid base catalyzed two step transesterification process of waste cooking oil, carried out at pre-determined optimum temperature of 65 C and 50 C for esterification and transesterification process respectively under the optimum condition of methanol to oil ratio of 3:7 (v/v), catalyst concentration 1%(w/w) for H{sub 2}SO{sub 4} and NaOH and 400 rpm of stirring. The optimum temperature was determined based on the yield of ME at different temperature. Simply, the optimum concentration of H{sub 2}SO{sub 4} and NaOH was determined with respect to ME Yield. The results indicated that both esterification and transesterification reaction are of first order rate reaction with reaction rate constant of 0.0031 min{sup -1} and 0.0078 min{sup -1} respectively showing that the former is a slower process than the later. The maximum yield of 21.50% of ME during esterification and 90.6% from transesterification of pretreated WCO has been obtained. This is the first study of its kind which deals with simplified kinetics of two step acid-base catalyzed transesterification process carried under the above optimum conditions and took about 6 h for complete conversion of TG to ME with least amount of activation energy. Also various parameters related to experiments are optimized with respect to ME yield. (author)

  19. Acid-base actuation of [c2]daisy chains.

    Fang, Lei; Hmadeh, Mohamad; Wu, Jishan; Olson, Mark A; Spruell, Jason M; Trabolsi, Ali; Yang, Ying-Wei; Elhabiri, Mourad; Albrecht-Gary, Anne-Marie; Stoddart, J Fraser

    2009-05-27

    A versatile synthetic strategy, which was conceived and employed to prepare doubly threaded, bistable [c2]daisy chain compounds, is described. Propargyl and 1-pentenyl groups have been grafted onto the stoppers of [c2]daisy chain molecules obtained using a template-directed synthetic protocol. Such [c2]daisy chain molecules undergo reversible extension and contraction upon treatment with acid and base, respectively. The dialkyne-functionalized [c2]daisy chain (AA) was subjected to an [AA+BB] type polymerization with an appropriate diazide (BB) to afford a linear, mechanically interlocked, main-chain polymer. The macromolecular properties of this polymer were characterized by chronocoulometry, size exclusion chromatography, and static light-scattering analysis. The acid-base switching properties of both the monomers and the polymer have been studied in solution, using (1)H NMR spectroscopy, UV/vis absorption spectroscopy, and cyclic voltammetry. The experimental results demonstrate that the functionalized [c2]daisy chains, along with their polymeric derivatives, undergo quantitative, efficient, and fully reversible switching processes in solution. Kinetics measurements demonstrate that the acid/base-promoted extension/contraction movements of the polymeric [c2]daisy chain are actually faster than those of its monomeric counterpart. These observations open the door to correlated molecular motions and to changes in material properties. PMID:19419175

  20. [Practical approach to complex acid-base disorders using a slide rule].

    Rives, E; Grimaud, D

    1986-01-01

    Diagnosis of mixed acid-base disturbances is often difficult. Nowadays it depends on biochemical and statistical interpretation, coupled with clinical data. The acid-base slide-rule is a useful tool to carry out this five step procedure, which it simplifies, giving rapidly at the patient's bed-side an objective support for the diagnosis of acid-base disturbances. PMID:3777572

  1. Acid-base interactions in microbial adhesion to hexadecane and chloroform

    Bos, R; Busscher, HJ; Geertsema-Doornbusch, GI; Van Der Mei, HC; Mittal, KL

    2000-01-01

    Acid-base interactions play an important role in adhesion, including microbial adhesion to surfaces. Qualitatively acid-base interactions in microbial adhesion can be demonstrated by comparing adhesion to hexadecane (a negatively charged interface in aqueous solutions, unable to exert acid-base inte

  2. Equilibrium Chemical Engines

    Shibata, Tatsuo; Sasa, Shin-ichi

    1997-01-01

    An equilibrium reversible cycle with a certain engine to transduce the energy of any chemical reaction into mechanical energy is proposed. The efficiency for chemical energy transduction is also defined so as to be compared with Carnot efficiency. Relevance to the study of protein motors is discussed. KEYWORDS: Chemical thermodynamics, Engine, Efficiency, Molecular machine.

  3. An Updated Equilibrium Machine

    Schultz, Emeric

    2008-01-01

    A device that can demonstrate equilibrium, kinetic, and thermodynamic concepts is described. The device consists of a leaf blower attached to a plastic container divided into two chambers by a barrier of variable size and form. Styrofoam balls can be exchanged across the barrier when the leaf blower is turned on and various air pressures are…

  4. Problems in equilibrium theory

    Aliprantis, Charalambos D

    1996-01-01

    In studying General Equilibrium Theory the student must master first the theory and then apply it to solve problems. At the graduate level there is no book devoted exclusively to teaching problem solving. This book teaches for the first time the basic methods of proof and problem solving in General Equilibrium Theory. The problems cover the entire spectrum of difficulty; some are routine, some require a good grasp of the material involved, and some are exceptionally challenging. The book presents complete solutions to two hundred problems. In searching for the basic required techniques, the student will find a wealth of new material incorporated into the solutions. The student is challenged to produce solutions which are different from the ones presented in the book.

  5. TBR-2 MHD equilibrium

    Determinations of many possible equilibrium configurations in a device is one of the most important phases of the project in the sense that plasma configurations basically determine the details of the machine project. Details as limiters, vacuum vessel configuration and the position of vertical field or shapping field coils. Recent progress of tokamaks with non circular poloidal section in the formation of different plasma shapes compared to traditional circular ones, made the determination of MHD equilibrium and becomes more essential. Tokamak TBR-2, to be constructed at the Institute of Physics of the University of Sao Paulo, is a device with this non-traditional quality. This paper shows the simulation results obtained for the TBR-2. (Author)

  6. Gated equilibrium bloodpool scintigraphy

    This thesis deals with the clinical applications of gated equilibrium bloodpool scintigraphy, performed with either a gamma camera or a portable detector system, the nuclear stethoscope. The main goal has been to define the value and limitations of noninvasive measurements of left ventricular ejection fraction as a parameter of cardiac performance in various disease states, both for diagnostic purposes as well as during follow-up after medical or surgical intervention. Secondly, it was attempted to extend the use of the equilibrium bloodpool techniques beyond the calculation of ejection fraction alone by considering the feasibility to determine ventricular volumes and by including the possibility of quantifying valvular regurgitation. In both cases, it has been tried to broaden the perspective of the observations by comparing them with results of other, invasive and non-invasive, procedures, in particular cardiac catheterization, M-mode echocardiography and myocardial perfusion scintigraphy. (Auth.)

  7. Equilibrium Cost Overruns

    Yongmin Chen; Ron Smith

    2001-01-01

    Cost overruns are endemic in military procurement projects and pervasive in other areas. This paper studies a model in which the apparent cost overruns arise not as systematic expectational errors but as equilibrium phenomena. The possibility of renegotiating payments when cost overruns occur results in firms bidding below their true estimate of expected project costs. This can cause the initial price for a project to be consistently lower than its expected cost, and hence the persistence of ...

  8. Volatility in Equilibrium

    Bollerslev, Tim; Sizova, Natalia; Tauchen, George

    Stock market volatility clusters in time, carries a risk premium, is fractionally inte- grated, and exhibits asymmetric leverage effects relative to returns. This paper develops a first internally consistent equilibrium based explanation for these longstanding empirical facts. The model is cast i......, and the dynamic cross-correlations of the volatility measures with the returns calculated from actual high-frequency intra-day data on the S&P 500 aggregate market and VIX volatility indexes....

  9. Bluffing: an equilibrium strategy

    Fabrice Rousseau

    1999-01-01

    The present work studies the behavior of a monopolistic informed trader in a two-period competitive dealer market. We show that the informed trader may engage in stock price manipulation as a result of the exploitation of his informational advantage (sufficient conditions are provided). The informed trader achieves this manipulation by not trading in the first period according to the information received. This trader attempts to jam his signal or to bluff. In equilibrium this behavior is anti...

  10. Equilibrium statistical mechanics

    Jackson, E Atlee

    2000-01-01

    Ideal as an elementary introduction to equilibrium statistical mechanics, this volume covers both classical and quantum methodology for open and closed systems. Introductory chapters familiarize readers with probability and microscopic models of systems, while additional chapters describe the general derivation of the fundamental statistical mechanics relationships. The final chapter contains 16 sections, each dealing with a different application, ordered according to complexity, from classical through degenerate quantum statistical mechanics. Key features include an elementary introduction t

  11. Exoplanet Equilibrium Chemistry Calculations

    Blumenthal, Sarah; Harrington, J.; Bowman, M.; Blecic, J.

    2013-10-01

    Recently, Agundez et al. (2012, A&A 548, A73) used a chemical kinetics code to study a model HD 209458b (equilibrium temperature of 1450 K, assuming full redistribution and 0 albedo). They found that thermochemistry dominates most of the dayside, but that significant compositional gradients may exist across the dayside. We calculate equilibrium-chemistry molecular abundances for several model exoplanets, using NASA's open-source Chemical Equilibrium Abundances code (McBride and Gordon 1996). We vary the degree of radiation redistribution to the dark side, ranging from total redistribution to instantaneous reradiation. Atomically, both the solar abundance multiple and the carbon fraction vary. Planet substellar temperatures range from just above 1200 K, where photochemistry should no longer be important, to those of hot planets (3000 K). We present synthetic abundance images for the key spectroscopic molecules CO, CH4, and H2O for several hot-Jupiter model planets. This work was supported by the NASA Planetary Atmospheres grant NNX12AI69G.

  12. Tourism Equilibrium Price Trends

    Mohammad Mohebi

    2012-01-01

    Full Text Available Problem statement: A review of the tourism history shows that tourism as an industry was virtually unknown in Malaysia until the late 1960s. Since then, it has developed and grown into a major industry, making an important contribution to the country's economy. By allocating substantial funds to the promotion of tourism and the provision of the necessary infrastructure, the government has played an important role in the impressive progress of the Malaysian tourism industry. One of the important factors which can attract tourists to Malaysia is the tourism price. Has the price of tourism decreased? To answer this question, it is necessary to obtain the equilibrium prices as well as the yearly trend for Malaysia during the sample period as it will be useful for analysis of the infrastructure situation of the tourism industry in this country. The purpose of the study is to identify equilibrium tourism price trends in Malaysian tourism market. Approach: We use hotel room as representative of tourism market. Quarterly data from 1995-2009 are used and a dynamic model of simultaneous equation is employed. Results: Based on the result during the period of 1995 until 2000, the growth rate of the equilibrium price was greater than consumer price index and producer price index. Conclusion: In the Malaysian tourism market, new infrastructure during this period had not been developed to keep pace with tourist arrivals.

  13. Non-equilibrium thermodynamics

    Groot, S R De

    2011-01-01

    The study of thermodynamics is especially timely today, as its concepts are being applied to problems in biology, biochemistry, electrochemistry, and engineering. This book treats irreversible processes and phenomena - non-equilibrium thermodynamics.S. R. de Groot and P. Mazur, Professors of Theoretical Physics, present a comprehensive and insightful survey of the foundations of the field, providing the only complete discussion of the fluctuating linear theory of irreversible thermodynamics. The application covers a wide range of topics: the theory of diffusion and heat conduction, fluid dyn

  14. Acid-base transport in pancreas – new challenges

    Ivana eNovak

    2013-12-01

    Full Text Available Along the gastrointestinal tract a number of epithelia contribute with acid or basic secretions in order to aid digestive processes. The stomach and pancreas are the most extreme examples of acid (H+ and base (HCO3- transporters, respectively. Nevertheless, they share the same challenges of transporting acid and bases across epithelia and effectively regulating their intracellular pH. In this review, we will make use of comparative physiology to enlighten the cellular mechanisms of pancreatic HCO3- and fluid secretion, which is still challenging physiologists. Some of the novel transporters to consider in pancreas are the proton pumps (H+-K+-ATPases, as well as the calcium-activated K+ and Cl- channels, such as KCa3.1 and TMEM16A/ANO1. Local regulators, such as purinergic signalling, fine-tune and coordinate pancreatic secretion. Lastly, we speculate whether dys-regulation of acid-base transport contributes to pancreatic diseases including cystic fibrosis, pancreatitis and cancer.

  15. Linear and nonlinear optical properties of nucleic acid bases

    Alparone, Andrea

    2013-01-01

    Electronic and vibrational (hyper)polarizabilities of neutral nucleic acid bases (uracil, thymine, cytosine, adenine, hypoxanthine and guanine) were determined using Hartree-Fock, correlated MPn (n = 2, 4), CCSD and DFT (B3LYP, B97-1, CAM-B3LYP) methods. The computations were performed in gaseous and aqueous phases for the most stable tautomeric forms. Frequency-dependent second-order hyperpolarizabilities were calculated for the OKE, IDRI, EFISHG and THG nonlinear optical processes at the wavelength of 1064 nm. The results show that the average electronic polarizabilities increase in the order uracil guanine. This order is also maintained for the electronic hyperpolarizabilities, with the inversion between cytosine and thymine. The response electric properties for the tautomers are almost similar to each other, whereas group substitution and solvation effects are much more significant. Among the DFT methods, the long-range corrected CAM-B3LYP functional gives the better performances, reproducing satisfactorily the correlated ab initio (hyper)polarizability data.

  16. [Development of Nucleic Acid-Based Adjuvant for Cancer Immunotherapy].

    Kobiyama, Kouji; Ishii, Ken J

    2015-09-01

    Since the discovery of the human T cell-defined tumor antigen, the cancer immunotherapy field has rapidly progressed, with the research and development of cancer immunotherapy, including cancer vaccines, being conducted actively. However, the disadvantages of most cancer vaccines include relatively weak immunogenicity and immune escape or exhaustion. Adjuvants with innate immunostimulatory activities have been used to overcome these issues, and these agents have been shown to enhance the immunogenicity of cancer vaccines and to act as mono-therapeutic anti-tumor agents. CpG ODN, an agonist for TLR9, is one of the promising nucleic acid-based adjuvants, and it is a potent inducer of innate immune effector functions. CpG ODN suppresses tumor growth in the absence of tumor antigens and peptide administration. Therefore, CpG ODN is expected to be useful as a cancer vaccine adjuvant as well as a cancer immunotherapy agent. In this review, we discuss the potential therapeutic applications and mechanisms of CpG ODN for cancer immunotherapy. PMID:26469159

  17. Money in search equilibrium, in competitive equilibrium, and in competitive search equilibrium

    Randall Wright; Guillame Rocheteau

    2004-01-01

    We compare three pricing mechanisms for monetary economies: bargaining (search equilibrium); price taking (competitive equilibrium); and price posting (competitive search equilibrium). We do this in a framework that, in addition to considering different mechanisms, extends existing work on the microfoundations of money by allowing a general matching technology and endogenous entry. We study how the nature of equilibrium and effects of policy depend on the mechanism. Under bargaining, trades a...

  18. A REVIEW ON ACID BASE STATUS IN DAIRY COWS: IMPLICATIONS OF DIETARY CATION-ANION BALANCE

    D. Afzaal, M. Nisa, M. A. Khan and M. Sarwar

    2004-01-01

    The acid base status of a dairy cow is maintained within a narrow range. The key mechanisms involving blood, cells and lungs, perform this function. Although other minerals have an impact on acid base metabolism, the minerals used in dietary cation-anion balance (DCAB) namely sodium (Na), potassium (K) and chloride (Cl) have the greatest effect. Hence, acid base status implicates other biological functions of dairy cows. Low DCAB prepartum reduces the incidence of milk fever and increases the...

  19. Acid-base thermochemistry of gaseous oxygen and sulfur substituted amino acids (Ser, Thr, Cys, Met).

    Riffet, Vanessa; Frison, Gilles; Bouchoux, Guy

    2011-11-01

    Acid-base thermochemistry of isolated amino acids containing oxygen or sulfur in their side chain (serine, threonine, cysteine and methionine) have been examined by quantum chemical computations. Density functional theory (DFT) was used, with B3LYP, B97-D and M06-2X functionals using the 6-31+G(d,p) basis set for geometry optimizations and the larger 6-311++G(3df,2p) basis set for energy computations. Composite methods CBS-QB3, G3B3, G4MP2 and G4 were applied to large sets of neutral, protonated and deprotonated conformers. Conformational analysis of these species, based on chemical approach and AMOEBA force field calculations, has been used to identify the lowest energy conformers and to estimate the population of conformers expected to be present at thermal equilibrium at 298 K. It is observed that G4, G4MP2, G3B3, CBS-QB3 composite methods and M06-2X DFT lead to similar conformer energies. Thermochemical parameters have been computed using either the most stable conformers or equilibrium populations of conformers. Comparison of experimental and theoretical proton affinities and Δ(acid)H shows that the G4 method provides the better agreement with deviations of less than 1.5 kJ mol(-1). From this point of view, a set of evaluated thermochemical quantities for serine, threonine, cysteine and methionine may be proposed: PA = 912, 919, 903, 938; GB = 878, 886, 870, 899; Δ(acid)H = 1393, 1391, 1396, 1411; Δ(acid)G = 1363, 1362, 1367, 1382 kJ mol(-1). This study also confirms that a non-negligible ΔpS° is associated with protonation of methionine and that the most acidic hydrogen of cysteine in the gas phase is that of the SH group. In several instances new conformers were identified thus suggesting a re-examination of several IRMPD spectra. PMID:21947236

  20. Statistical physics ""Beyond equilibrium

    Ecke, Robert E [Los Alamos National Laboratory

    2009-01-01

    The scientific challenges of the 21st century will increasingly involve competing interactions, geometric frustration, spatial and temporal intrinsic inhomogeneity, nanoscale structures, and interactions spanning many scales. We will focus on a broad class of emerging problems that will require new tools in non-equilibrium statistical physics and that will find application in new material functionality, in predicting complex spatial dynamics, and in understanding novel states of matter. Our work will encompass materials under extreme conditions involving elastic/plastic deformation, competing interactions, intrinsic inhomogeneity, frustration in condensed matter systems, scaling phenomena in disordered materials from glasses to granular matter, quantum chemistry applied to nano-scale materials, soft-matter materials, and spatio-temporal properties of both ordinary and complex fluids.

  1. Equilibrium models and variational inequalities

    Konnov, Igor

    2007-01-01

    The concept of equilibrium plays a central role in various applied sciences, such as physics (especially, mechanics), economics, engineering, transportation, sociology, chemistry, biology and other fields. If one can formulate the equilibrium problem in the form of a mathematical model, solutions of the corresponding problem can be used for forecasting the future behavior of very complex systems and, also, for correcting the the current state of the system under control. This book presents a unifying look on different equilibrium concepts in economics, including several models from related sciences.- Presents a unifying look on different equilibrium concepts and also the present state of investigations in this field- Describes static and dynamic input-output models, Walras, Cassel-Wald, spatial price, auction market, oligopolistic equilibrium models, transportation and migration equilibrium models- Covers the basics of theory and solution methods both for the complementarity and variational inequality probl...

  2. Canonical Pedagogical Content Knowledge by Cores for Teaching Acid-Base Chemistry at High School

    Alvarado, Clara; Cañada, Florentina; Garritz, Andoni; Mellado, Vicente

    2015-01-01

    The topic of acid-base chemistry is one of the oldest in general chemistry courses and it has been almost continuously in academic discussion. The central purpose of documenting the knowledge and beliefs of a group of ten Mexican teachers with experience in teaching acid-base chemistry in high school was to know how they design, prepare and…

  3. Para-equilibrium phase diagrams

    Highlights: • A rapidly cooled system may attain a state of para-equilibrium. • In this state rapidly diffusing elements reach equilibrium but others are immobile. • Application of the Phase Rule to para-equilibrium phase diagrams is discussed. • A general algorithm to calculate para-equilibrium phase diagrams is described. - Abstract: If an initially homogeneous system at high temperature is rapidly cooled, a temporary para-equilibrium state may result in which rapidly diffusing elements have reached equilibrium but more slowly diffusing elements have remained essentially immobile. The best known example occurs when homogeneous austenite is quenched. A para-equilibrium phase assemblage may be calculated thermodynamically by Gibbs free energy minimization under the constraint that the ratios of the slowly diffusing elements are the same in all phases. Several examples of calculated para-equilibrium phase diagram sections are presented and the application of the Phase Rule is discussed. Although the rules governing the geometry of these diagrams may appear at first to be somewhat different from those for full equilibrium phase diagrams, it is shown that in fact they obey exactly the same rules with the following provision. Since the molar ratios of non-diffusing elements are the same in all phases at para-equilibrium, these ratios act, as far as the geometry of the diagram is concerned, like “potential” variables (such as T, pressure or chemical potentials) rather than like “normal” composition variables which need not be the same in all phases. A general algorithm to calculate para-equilibrium phase diagrams is presented. In the limit, if a para-equilibrium calculation is performed under the constraint that no elements diffuse, then the resultant phase diagram shows the single phase with the minimum Gibbs free energy at any point on the diagram; such calculations are of interest in physical vapor deposition when deposition is so rapid that phase

  4. Nash equilibrium with Sugeno payoff

    Radul, Taras

    2015-01-01

    This paper is devoted to Nash equilibrium for games in capacities. Such games with payoff expressed by Choquet integral were considered by Kozhan and Zarichnyi (Nash equilibria for games in capacities, Econ. Theory {\\bf 35} (2008) 321--331) and existence of Nash equilibrium was proved. We also consider games in capacities but with expected payoff expressed by Sugeno integral. We prove existence of Nash equilibrium using categorical methods and abstract convexity theory.

  5. Models for Equilibrium BEC Superradiance

    Pulé, J V; Zagrebnov, V A; Pule, Joseph V.; Verbeure, Andre; Zagrebnov, Valentin A.

    2004-01-01

    Motivated by recent experiments with superradiant Bose-Einstein Condensate (BEC) we consider simple microscopic models describing rigorously the interference of the two cooperative phenomena, BEC and radiation, in thermodynamic equilibrium. Our resuts in equilibrium confirm the presence of the observed superradiant light scattering from BEC: (a) the equilibrium superradiance exists only below a certain transition temperature; (b) there is superradiance and matter-wave (BEC) enhancement due to the coherent coupling between light and matter.

  6. Models for Equilibrium BEC Superradiance

    Pule, Joseph V.; Verbeure, Andre; Zagrebnov, Valentin A.

    2004-01-01

    Motivated by recent experiments with superradiant Bose-Einstein Condensate (BEC) we consider simple microscopic models describing rigorously the interference of the two cooperative phenomena, BEC and radiation, in thermodynamic equilibrium. Our resuts in equilibrium confirm the presence of the observed superradiant light scattering from BEC: (a) the equilibrium superradiance exists only below a certain transition temperature; (b) there is superradiance and matter-wave (BEC) enhancement due to...

  7. Models for equilibrium BEC superradiance

    Motivated by recent experiments with superradiant Bose-Einstein condensate (BEC) we consider simple microscopic models describing rigorously the interference of the two cooperative phenomena, BEC and radiation, in thermodynamic equilibrium. Our results in equilibrium confirm the presence of the observed superradiant light scattering from BEC: (a) the equilibrium superradiance exists only below a certain transition temperature; (b) there is superradiance and matter-wave (BEC) enhancement due to the coherent coupling between light and matter. (letter to the editor)

  8. Equilibrium Electro-osmotic Instability

    Rubinstein, Isaak; Zaltzman, Boris

    2014-01-01

    Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium elect...

  9. Simplex characterization of equilibrium

    Minimization of the reaction isotherm absolute value by the sequential simplex method may be used to characterize the equilibrium valence state distribution of plutonium in aqueous solutions. Sequential simplex procedure is an empirical method of locating maxima or minima in the response of a function of several variables. Where the objective function is entirely mathematical, a computer may be used to perform the simplex operations in a rapid and accurate manner, so that maxima and minima can often be located quickly and easily. The disproportionation of tetravalent plutonium is considered to be the consequence of two sequential reactions: 2Pu4+ + 2HOH = Pu3+ + PuO2+ + 4H+ P (1). Pu4+ + PuO2+ = Pu3+ + PuO2+ Q (2). If P is the frequency of occurrence of Eq. (1), and Q is the frequency of occurrence of Eq. (2), then it is assumed, that P=Q, and Eqs (1) and (2) may be added directly. 3Pu4+ + 2HOH = 2Pu3+ + PuO22+ + 4H+ (3). The persistence of pentavalent plutonium in aqueous plutonium solutions suggests that reactions 1 and 2 are not of equal frequency, and that their proportion for purposes of addition is not exactly equal to 1:1. (T.I.)

  10. Thermodynamic chemical energy transfer mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium chemical reactions

    Chemical energy transfer mechanisms at finite temperature are explored by a chemical energy transfer theory which is capable of investigating various chemical mechanisms of non-equilibrium, quasi-equilibrium, and equilibrium. Gibbs energy fluxes are obtained as a function of chemical potential, time, and displacement. Diffusion, convection, internal convection, and internal equilibrium chemical energy fluxes are demonstrated. The theory reveals that there are chemical energy flux gaps and broken discrete symmetries at the activation chemical potential, time, and displacement. The statistical, thermodynamic theory is the unification of diffusion and internal convection chemical reactions which reduces to the non-equilibrium generalization beyond the quasi-equilibrium theories of migration and diffusion processes. The relationship between kinetic theories of chemical and electrochemical reactions is also explored. The theory is applied to explore non-equilibrium chemical reactions as an illustration. Three variable separation constants indicate particle number constants and play key roles in describing the distinct chemical reaction mechanisms. The kinetics of chemical energy transfer accounts for the four control mechanisms of chemical reactions such as activation, concentration, transition, and film chemical reactions. - Highlights: • Chemical energy transfer theory is proposed for non-, quasi-, and equilibrium. • Gibbs energy fluxes are expressed by chemical potential, time, and displacement. • Relationship between chemical and electrochemical reactions is discussed. • Theory is applied to explore nonequilibrium energy transfer in chemical reactions. • Kinetics of non-equilibrium chemical reactions shows the four control mechanisms

  11. Kinetic equilibrium and relativistic thermodynamics

    Ván P.

    2011-01-01

    Relativistic thermodynamics is treated from the point of view of kinetic theory. It is shown that the generalized J\\"uttner distribution suggested in [1] is compatible with kinetic equilibrium. The requirement of compatibility of kinetic and thermodynamic equilibrium reveals several generalizations of the Gibbs relation where the velocity field is an independent thermodynamic variable.

  12. Non-equilibrium phase transitions

    Henkel, Malte; Lübeck, Sven

    2009-01-01

    This book describes two main classes of non-equilibrium phase-transitions: (a) static and dynamics of transitions into an absorbing state, and (b) dynamical scaling in far-from-equilibrium relaxation behaviour and ageing. The first volume begins with an introductory chapter which recalls the main concepts of phase-transitions, set for the convenience of the reader in an equilibrium context. The extension to non-equilibrium systems is made by using directed percolation as the main paradigm of absorbing phase transitions and in view of the richness of the known results an entire chapter is devoted to it, including a discussion of recent experimental results. Scaling theories and a large set of both numerical and analytical methods for the study of non-equilibrium phase transitions are thoroughly discussed. The techniques used for directed percolation are then extended to other universality classes and many important results on model parameters are provided for easy reference.

  13. A Multiperiod Equilibrium Pricing Model

    Minsuk Kwak

    2014-01-01

    Full Text Available We propose an equilibrium pricing model in a dynamic multiperiod stochastic framework with uncertain income. There are one tradable risky asset (stock/commodity, one nontradable underlying (temperature, and also a contingent claim (weather derivative written on the tradable risky asset and the nontradable underlying in the market. The price of the contingent claim is priced in equilibrium by optimal strategies of representative agent and market clearing condition. The risk preferences are of exponential type with a stochastic coefficient of risk aversion. Both subgame perfect strategy and naive strategy are considered and the corresponding equilibrium prices are derived. From the numerical result we examine how the equilibrium prices vary in response to changes in model parameters and highlight the importance of our equilibrium pricing principle.

  14. A REVIEW ON ACID BASE STATUS IN DAIRY COWS: IMPLICATIONS OF DIETARY CATION-ANION BALANCE

    D. Afzaal, M. Nisa, M. A. Khan and M. Sarwar

    2004-10-01

    Full Text Available The acid base status of a dairy cow is maintained within a narrow range. The key mechanisms involving blood, cells and lungs, perform this function. Although other minerals have an impact on acid base metabolism, the minerals used in dietary cation-anion balance (DCAB namely sodium (Na, potassium (K and chloride (Cl have the greatest effect. Hence, acid base status implicates other biological functions of dairy cows. Low DCAB prepartum reduces the incidence of milk fever and increases the productivity by simmering down the severity of hypocalcaemia. High DCAB diets have proved to increase dry mater and water intake and production and to mitigate the effects of heat stress.

  15. Equilibrium relationships for non-equilibrium chemical dependencies

    Yablonsky, Gregory S; Marin, Guy B

    2010-01-01

    In contrast to common opinion, it is shown that equilibrium constants determine the time-dependent behavior of particular ratios of concentrations for any system of reversible first-order reactions. Indeed, some special ratios actually coincide with the equilibrium constant at any moment in time. This is established for batch reactors, and similar relations hold for steady-state plug-flow reactors, replacing astronomic time by residence time. Such relationships can be termed time invariants of chemical kinetics.

  16. Helical axis stellarator equilibrium model

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift

  17. Equilibrium with arbitrary market structure

    Grodal, Birgit; Vind, Karl

    2005-01-01

    complete market predicted by this theory is clearly unrealistic, and Radner [10] formulated and proved existence of equilibrium in a multiperiod model with incomplete markets. In this paper the Radner result is extended. Radner assumed a specific structure of markets, independence of preferences......Fifty years ago Arrow [1] introduced contingent commodities and Debreu [4] observed that this reinterpretation of a commodity was enough to apply the existing general equilibrium theory to uncertainty and time. This interpretation of general equilibrium theory is the Arrow-Debreu model. The...

  18. Recent advances in understanding trans-epithelial acid-base regulation and excretion mechanisms in cephalopods

    Hu, Marian Y.; Hwang, Pung-Pung; Tseng, Yung-Che

    2015-01-01

    Cephalopods have evolved complex sensory systems and an active lifestyle to compete with fish for similar resources in the marine environment. Their highly active lifestyle and their extensive protein metabolism has led to substantial acid-base regulatory abilities enabling these organisms to cope with CO2 induced acid-base disturbances. In convergence to teleost, cephalopods possess an ontogeny-dependent shift in ion-regulatory epithelia with epidermal ionocytes being the major site of embry...

  19. On Generalized Vector Equilibrium Problems

    An-hua Wan; Jun-yi Fu; Wei-hua Mao

    2006-01-01

    A new generalized vector equilibrium problem involving set-valued mappings and the proper quasi-concavity of set-valued mappings in topological vector spaces are introduced; its existence theorems and the convexity of the solution sets are established.

  20. On the local equilibrium condition

    A physical system is in local equilibrium if it cannot be distinguished from a global equilibrium by ''infinitesimally localized measurements''. This should be a natural characterization of local equilibrium, but the problem is to give a precise meaning to the qualitative phrase ''infinitesimally localized measurements''. A solution is suggested in form of a Local Equilibrium Condition (LEC), which can be applied to linear relativistic quantum field theories but not directly to selfinteracting quantum fields. The concept of local temperature resulting from LEC is compared to an old approach to local temperature based on the principle of maximal entropy. It is shown that the principle of maximal entropy does not always lead to physical states if it is applied to relativistic quantum field theories. (orig.)

  1. Equilibrium Electro-osmotic Instability

    Rubinstein, Isaak

    2014-01-01

    Since its prediction fifteen years ago, electro-osmotic instability has been attributed to non-equilibrium electro-osmosis related to the extended space charge which develops at the limiting current in the course of concentration polarization at a charge-selective interface. This attribution had a double basis. Firstly, it has been recognized that equilibrium electro-osmosis cannot yield instability for a perfectly charge-selective solid. Secondly, it has been shown that non-equilibrium electro-osmosis can. First theoretical studies in which electro-osmotic instability was predicted and analyzed employed the assumption of perfect charge-selectivity for the sake of simplicity and so did the subsequent numerical studies of various time-dependent and nonlinear features of electro-osmotic instability. In this letter, we show that relaxing the assumption of perfect charge-selectivity (tantamount to fixing the electrochemical potential in the solid) allows for equilibrium electro-osmotic instability. Moreover, we s...

  2. Equilibrium Distribution of Labor Productivity

    Aoyama, Hideaki; Iyetomi, Hiroshi; Yoshikawa, Hiroshi

    2012-01-01

    We construct a theoretical model for equilibrium distribution of workers across sectors with different labor productivity, assuming that a sector can accommodate a limited number of workers which depends only on its productivity. A general formula for such distribution of productivity is obtained, using the detail-balance condition necessary for equilibrium in the Ehrenfest-Brillouin model. We also carry out an empirical analysis on the average number of workers in given productivity sectors ...

  3. Conformity, Equity and Correlated Equilibrium

    Edward Cartwright; Myrna Wooders

    2008-01-01

    We explore the potential for correlated equilibrium to capture conformity to norms and the coordination of behavior within social groups. Given a partition of players into social groups we propose three properties one may expect of a correlated equilibrium: within-group anonymity, group independence and stereotyped beliefs. Within-group anonymity requires that players within the same social group have equal opportunities and equal payoffs. Group independence requires that there be no correlat...

  4. Equilibrium wage-tenure contracts

    Burdett, K.; Coles, Melvin G.

    2003-01-01

    In this study we consider a labor market matching model where firms post wage-tenure contracts and workers, both employed and unemployed, search for new job opportunities. Given workers are risk averse, we establish there is a unique equilibrium in the environment considered. Although firms in the market make different offers in equilibrium, all post a wage-tenure contract that implies a worker's wage increases smoothly with tenure at the firm. As firms make different offers, there is job tur...

  5. The Alternative to Equilibrium Existence

    David Rahman

    2008-01-01

    This paper establishes and interprets a necessary and sucient condition for existence of (countably additive) correlated equilibrium in n-person games, assuming only that utility functions are bounded, measurable. A sequence of deviation profiles is consistent if there exists a correlated strategy that makes every profile in the sequence unprofitable with respect to the sum of utilities. An equilibrium exists if and only if every sequence of deviation profiles has a consistent subsequence. Th...

  6. Generalized Market Equilibrium: "Stable" CAPM

    Belkacem, Lotfi; Lévy Véhel, Jacques; Walter, Christian

    1995-01-01

    Our main purpose in this paper is to derive the generalized equilibrium relationship between risk and return under the assumption that the asset returns follow a joint symmetric stable distribution. We show that equilibrium rates of return on all risky assets are functions of their covariation with the market portfolio. The "stable" CAPM highlights a new measure of the quantity of risk which may be interpreted as a "generalized beta coefficient".

  7. A Communication Proof Equilibrium Concept

    Ferreira, José Luis

    1996-01-01

    This paper proposes an equilibrium concept for the classes of environments in which players can cornmunicate with each other but cannot rnake binding agreernents. This Cornmunication-proof equilibrium is intended to be regarded as an extension of both Coalition and Renegotiation-proof equilibria. Conceptual foundations for this particular definition are widely discussed as it is confronted with other definitions in this class of environments. The definition is extended to in...

  8. Shape characteristics of equilibrium and non-equilibrium fractal clusters

    Mansfield, Marc L.; Douglas, Jack F.

    2013-07-01

    It is often difficult in practice to discriminate between equilibrium and non-equilibrium nanoparticle or colloidal-particle clusters that form through aggregation in gas or solution phases. Scattering studies often permit the determination of an apparent fractal dimension, but both equilibrium and non-equilibrium clusters in three dimensions frequently have fractal dimensions near 2, so that it is often not possible to discriminate on the basis of this geometrical property. A survey of the anisotropy of a wide variety of polymeric structures (linear and ring random and self-avoiding random walks, percolation clusters, lattice animals, diffusion-limited aggregates, and Eden clusters) based on the principal components of both the radius of gyration and electric polarizability tensor indicates, perhaps counter-intuitively, that self-similar equilibrium clusters tend to be intrinsically anisotropic at all sizes, while non-equilibrium processes such as diffusion-limited aggregation or Eden growth tend to be isotropic in the large-mass limit, providing a potential means of discriminating these clusters experimentally if anisotropy could be determined along with the fractal dimension. Equilibrium polymer structures, such as flexible polymer chains, are normally self-similar due to the existence of only a single relevant length scale, and are thus anisotropic at all length scales, while non-equilibrium polymer structures that grow irreversibly in time eventually become isotropic if there is no difference in the average growth rates in different directions. There is apparently no proof of these general trends and little theoretical insight into what controls the universal anisotropy in equilibrium polymer structures of various kinds. This is an obvious topic of theoretical investigation, as well as a matter of practical interest. To address this general problem, we consider two experimentally accessible ratios, one between the hydrodynamic and gyration radii, the other

  9. Quantum Statistical Mechanics. III. Equilibrium Probability

    Attard, Phil

    2014-01-01

    Given are a first principles derivation and formulation of the probabilistic concepts that underly equilibrium quantum statistical mechanics. The transition to non-equilibrium probability is traversed briefly.

  10. Physicochemical Perturbations of Phase Equilibriums

    Dobruskin, Vladimir Kh

    2010-01-01

    The alternative approach to the displacement of gas/liquid equilibrium is developed on the basis of the Clapeyron equation. The phase transition in the system with well-established properties is taken as a reference process to search for the parameters of phase transition in the perturbed equilibrium system. The main equation, derived in the framework of both classical thermodynamics and statistical mechanics, establishes a correlation between variations of enthalpies of evaporation, \\Delta (\\Delta H), which is induced by perturbations, and the equilibrium vapor pressures. The dissolution of a solute, changing the surface shape, and the effect of the external field of adsorbents are considered as the perturbing actions on the liquid phase. The model provides the unified method for studying (1) solutions, (2) membrane separations (3) surface phenomena, and (4) effect of the adsorption field; it leads to the useful relations between \\Delta (\\Delta H), on the one hand, and the osmotic pressures, the Donnan poten...

  11. Equilibrium in a Production Economy

    Chiarolla, Maria B., E-mail: maria.chiarolla@uniroma1.it [Universita di Roma ' La Sapienza' , Dipartimento di Metodi e Modelli per l' Economia, il Territorio e la Finanza, Facolta di Economia (Italy); Haussmann, Ulrich G., E-mail: uhaus@math.ubc.ca [University of British Columbia, Department of Mathematics (Canada)

    2011-06-15

    Consider a closed production-consumption economy with multiple agents and multiple resources. The resources are used to produce the consumption good. The agents derive utility from holding resources as well as consuming the good produced. They aim to maximize their utility while the manager of the production facility aims to maximize profits. With the aid of a representative agent (who has a multivariable utility function) it is shown that an Arrow-Debreu equilibrium exists. In so doing we establish technical results that will be used to solve the stochastic dynamic problem (a case with infinite dimensional commodity space so the General Equilibrium Theory does not apply) elsewhere.

  12. Equilibrium in a Production Economy

    Consider a closed production-consumption economy with multiple agents and multiple resources. The resources are used to produce the consumption good. The agents derive utility from holding resources as well as consuming the good produced. They aim to maximize their utility while the manager of the production facility aims to maximize profits. With the aid of a representative agent (who has a multivariable utility function) it is shown that an Arrow-Debreu equilibrium exists. In so doing we establish technical results that will be used to solve the stochastic dynamic problem (a case with infinite dimensional commodity space so the General Equilibrium Theory does not apply) elsewhere.

  13. Torsatron equilibrium and stability studies

    Equilibrium and stability results are presented for the Advanced Toroidal Facility (ATF) device. The results of three-dimensional equilibrium calculations and free boundary average method calculations are shown to be in good agreement with previous fixed boundary average method results. These favorable comparisons serve as a valuable validation of the simple and computationally efficient fixed boundary average method. Stability calculations for the free boundary average method equilibria are also in good agreement with fixed boundary calculations, showing instability only when the plasma is shifted inward with an applied vertical field

  14. Theoretical study of the influence of ribose on the proton transfer phenomenon of nucleic acid bases

    The first comprehensive theoretical study of ribose's effects on the behavior of proton transfer of nucleic acid base is presented. The specific hydrogen bonding of the ribose hydroxyls plays a very important role in the stabilization of the structure of ribonucleoside. Nine stable uridine conformations have been reported. The intermolecular proton transfer of the isolated, monohydrated uridine complexes in three different regions were extensively explored on the basis of density functional theory at the B3LYP/6-31+G* level. With the introduction of the ribose, not only the structural parameters of the nucleic acid bases changed, but also the energy barriers of the proton transfer process changed. Furthermore, changes of the electron distributions of the molecular orbital of the nucleic acid bases were also analyzed by NBO analysis. Consideration of the ribose's influence represents a much more real situation in the RNA

  15. Effect of acute acid loading on acid-base and calcium metabolism

    Osther, Palle J

    2006-01-01

    OBJECTIVE: To investigate the acid-base and calcium metabolic responses to acute non-carbonic acid loading in idiopathic calcium stone-formers and healthy males using a quantitative organ physiological approach. MATERIAL AND METHODS: Five-h ammonium chloride loading studies were performed in 12...... male recurrent idiopathic calcium stone-formers and 12 matched healthy men using a randomized, placebo-controlled, cross-over design. Arterialized capillary blood, serum and urine were collected hourly for measurement of electrolytes, ionized calcium, magnesium, phosphate, parathyroid hormone and acid-base...... status. Concentrations of non-metabolizable base (NB) and acid (NA) were calculated from measured concentrations of non-metabolizable ions. RESULTS: The extracellular acid-base status in the stone-formers during basal conditions and acid loading was comparable to the levels in the healthy controls...

  16. The in Silico Insight into Carbon Nanotube and Nucleic Acid Bases Interaction

    Karimi, Ali Asghar; Ghalandari, Behafarid; Tabatabaie, Seyed Saleh; Farhadi, Mohammad

    2016-01-01

    Background To explore practical applications of carbon nanotubes (CNTs) in biomedical fields the properties of their interaction with biomolecules must be revealed. Recent years, the interaction of CNTs with biomolecules is a subject of research interest for practical applications so that previous research explored that CNTs have complementary structure properties with single strand DNA (ssDNA). Objectives Hence, the quantum mechanics (QM) method based on ab initio was used for this purpose. Therefore values of binding energy, charge distribution, electronic energy and other physical properties of interaction were studied for interaction of nucleic acid bases and SCNT. Materials and Methods In this study, the interaction between nucleic acid bases and a (4, 4) single-walled carbon nanotube (SCNT) were investigated through calculations within quantum mechanics (QM) method at theoretical level of Hartree-Fock (HF) method using 6-31G basis set. Hence, the physical properties such as electronic energy, total dipole moment, charge distributions and binding energy of nucleic acid bases interaction with SCNT were investigated based on HF method. Results It has been found that the guanine base adsorption is bound stronger to the outer surface of nanotube in comparison to the other bases, consistent with the recent theoretical studies. In the other words, the results explored that guanine interaction with SCNT has optimum level of electronic energy so that their interaction is stable. Also, the calculations illustrated that SCNT interact to nucleic acid bases by noncovalent interaction because of charge distribution an electrostatic area is created in place of interaction. Conclusions Consequently, small diameter SCNT interaction with nucleic acid bases is noncovalent. Also, the results revealed that small diameter SCNT interaction especially SCNT (4, 4) with nucleic acid bases can be useful in practical application area of biomedical fields such detection and drug delivery.

  17. Opuntia ficus indica (L. Fruit Extract as Natural Indicator in Acid-Base Titration

    Manoj A. Suva

    2014-03-01

    Full Text Available In routine experiments synthetic indicators are the choice of acid base titrations. But there are some limitations like environmental pollution, availability and higher cost which leads to search for natural compounds as an acid base indicator was started. The present work highlights theexploit of the methanolic and aqueous extract of the fruit of Opuntia ficus indica plants as a natural acid base indicator in acid base titrations. Opuntia ficus indica plant was identified and fruits were washed and cleaned by distilled water, grinded by a mechanical blender and soaked in 50ml methanol for 48 hours and then triturated in mortal and pestle and the resulting solution were filtered through muslin cloth. The resulted methanolic extract and aqueous extract which was prepared by heating fruits in water for half an hour and filtered used as natural indicator foracidimetry and alkalimetry. For each type of acid base titrations t-value and standard deviation were calculated from results obtained. Natural indicator is easy to prepare, easily available and have no toxic effects and promising results were obtained when it was tested against standard synthetic indicators. Titration shows sharp colour change at the equivalence point. The equivalence points (end points obtained by the fruit extract correlate with the equivalence points obtained by standard indicators. In strong acid and strong base titration, the results obtained in the fruit's extract matched with the results obtained by standard indicator. Hence, natural indicator is found to be a very useful, readily available, nonhazardous, economical, simple to prepare and accurate for the acid-base titrations.

  18. Non-Stationary Search Equilibrium

    Fabien Postel-Vinay; Giuseppe Moscarini

    2009-01-01

    We study aggregate equilibrium dynamics of a frictional labor market where firms post employment contracts and workers search randomly on and off the job for such contracts, while the economy is hit by aggregate productivity shocks. Our exercise provides the first analysis of aggregate dynamics of a popular class of search wage-posting models with undirected job search.

  19. Incentives in Supply Function Equilibrium

    Vetter, Henrik

    2014-01-01

    The author analyses delegation in homogenous duopoly under the assumption that the firm-managers compete in supply functions. In supply function equilibrium, managers’ decisions are strategic complements. This reverses earlier findings in that the author finds that owners give managers incentives...

  20. Financial equilibrium with career concerns

    Amil Dasgupta

    2006-03-01

    Full Text Available What are the equilibrium features of a financial market where a sizeable proportion of traders face reputational concerns? This question is central to our understanding of financial markets, which are increasingly dominated by institutional investors. We construct a model of delegated portfolio management that captures key features of the US mutual fund industry and embed it in an asset pricing framework. We thus provide a formal model of financial equilibrium with career concerned agents. Fund managers differ in their ability to understand market fundamentals, and in every period investors choose a fund. In equilibrium, the presence of career concerns induces uninformed fund managers to churn, i.e., to engage in trading even when they face a negative expected return. Churners act as noise traders and enhance the level of trading volume. The equilibrium relationship between fund return and net fund flows displays a skewed shape that is consistent with stylized facts. The robustness of our core results is probed from several angles.

  1. Studies on synthesis and property of novel acid-base proton exchange membranes

    Yong Fang Liang; Hai Yan Pan; Xiu Ling Zhu; Yao Xia Zhang; Xi Gao Jian

    2007-01-01

    Sulfonated poly(phthalazinone)s (SPPENK, SPPESK and SPPBEK) were prepared by direct polymerization reaction from sulfonated monomers. The novel acid-base membranes were composed of sulfonated polymers as the acidic compounds, and polyetherimide (PEI) as the basic compounds, casting from their N-methylpyrrolidone (NMP) solution directly onto clean glass plates at 60 ℃ aiming at enhancing membrane toughness and other relative properties. The resulted acid-base composite membranes had excellent resistance to swelling, thermo-stability, hydrolysis resistance and oxidative resistance properties with highly ion-exchange capacity (IEC).

  2. Bifunctional Organic Polymeric Catalysts with a Tunable Acid-Base Distance and Framework Flexibility

    Chen, Huanhui; Wang, Yanan; Wang, Qunlong; Li, Junhui; Yang, Shiqi; Zhu, Zhirong

    2014-09-01

    Acid-base bifunctional organic polymeric catalysts were synthesized with tunable structures. we demonstrated two synthesis approaches for structural fine-tune. In the first case, the framework flexibility was tuned by changing the ratio of rigid blocks to flexible blocks within the polymer framework. In the second case, we precisely adjusted the acid-base distance by distributing basic monomers to be adjacent to acidic monomers, and by changing the chain length of acidic monomers. In a standard test reaction for the aldol condensation of 4-nitrobenzaldehyde with acetone, the catalysts showed good reusability upon recycling and maintained relatively high conversion percentage.

  3. Calculating acid-base and oxygenation status during COPD exacerbation using mathematically arterialised venous blood

    Rees, Stephen Edward; Rychwicka-Kielek, Beate A; Andersen, Bjarne F;

    2012-01-01

    Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission for exacerbat......Abstract Background: Repeated arterial puncture is painful. A mathematical method exists for transforming peripheral venous pH, PCO2 and PO2 to arterial eliminating the need for arterial sampling. This study evaluates this method to monitor acid-base and oxygenation during admission...

  4. Acid-base regulation in tadpoles of Rana catesbeiana exposed to environmental hypercapnia

    Busk, Morten; Larsen, Erik Hviid; Jensen, Frank B.

    1997-01-01

    Tadpoles of Rana catesbeiana were exposed to different levels of environmental hypercapnia. The acid-base regulatory response differed from that in adult amphibians in showing a high degree of pH compensation in the extracellular fluid (65-85%) and complete compensation in the intracellular fluid......). It is suggested that the large bicarbonate efflux from the animal is a consequence of the dissolution of CaCO3 stores and the delayed adjustment of bicarbonate-retaining mechanisms. Re-exposure of tadpoles to hypercapnia after 1-3 weeks of normocapnic recovery only affected transepithelial fluxes of acid-base...

  5. Nucleic Acid-based Detection of Bacterial Pathogens Using Integrated Microfluidic Platform Systems

    Carl A. Batt

    2009-05-01

    Full Text Available The advent of nucleic acid-based pathogen detection methods offers increased sensitivity and specificity over traditional microbiological techniques, driving the development of portable, integrated biosensors. The miniaturization and automation of integrated detection systems presents a significant advantage for rapid, portable field-based testing. In this review, we highlight current developments and directions in nucleic acid-based micro total analysis systems for the detection of bacterial pathogens. Recent progress in the miniaturization of microfluidic processing steps for cell capture, DNA extraction and purification, polymerase chain reaction, and product detection are detailed. Discussions include strategies and challenges for implementation of an integrated portable platform.

  6. The concept of equilibrium in organization theory

    Gazendam, Henk W.M.

    1997-01-01

    Many organization theories consist of an interpretation frame and an idea about the ideal equilibrium state. This article explains how the equilibrium concept is used in four organization theories: the theories of Fayol, Mintzberg, Morgan, and Volberda. Equilibrium can be defined as balance, fit or requisite variety. Equilibrium is related to observables dependent on the definition of organization as work organization, formal organization or artifact organization. Equilibrium can be explicitl...

  7. Competitive equilibrium with search frictions : a general equilibrium approach

    Jerez, Belén

    2012-01-01

    When the trading process is characterized by search frictions, traders may be rationed so markets need not clear. We build a general equilibrium model with transferable utility where the uncertainty arising from rationing is incorporated in the definition of a commodity, in the spirit of the Arrow-Debreu theory. Prices of commodities then depend not only on their physical characteristics, but also on the probability that their trade is rationed. The standard definition of competitive equilibr...

  8. Non-Equilibrium Properties from Equilibrium Free Energy Calculations

    Pohorille, Andrew; Wilson, Michael A.

    2012-01-01

    Calculating free energy in computer simulations is of central importance in statistical mechanics of condensed media and its applications to chemistry and biology not only because it is the most comprehensive and informative quantity that characterizes the eqUilibrium state, but also because it often provides an efficient route to access dynamic and kinetic properties of a system. Most of applications of equilibrium free energy calculations to non-equilibrium processes rely on a description in which a molecule or an ion diffuses in the potential of mean force. In general case this description is a simplification, but it might be satisfactorily accurate in many instances of practical interest. This hypothesis has been tested in the example of the electrodiffusion equation . Conductance of model ion channels has been calculated directly through counting the number of ion crossing events observed during long molecular dynamics simulations and has been compared with the conductance obtained from solving the generalized Nernst-Plank equation. It has been shown that under relatively modest conditions the agreement between these two approaches is excellent, thus demonstrating the assumptions underlying the diffusion equation are fulfilled. Under these conditions the electrodiffusion equation provides an efficient approach to calculating the full voltage-current dependence routinely measured in electrophysiological experiments.

  9. The scaled-charge additive force field for amino acid based ionic liquids

    Fileti, E. E.; Chaban, V. V.

    2014-01-01

    Ionic liquids (ILs) constitute an emerging research field. New ILs involve more and more organic and inorganic ions. Amino acid based ILs (AAILs) represent a specific interest due to their evolutional connection to proteins. We report a new non-polarizable force field (FF) for the eight AAILs...

  10. Design, synthesis and structure of new potential electrochemically active boronic acid-based glucose sensors

    Norrild, Jens Chr.; Søtofte, Inger

    2002-01-01

    In the course of our investigations on new boronic acid based carbohydrate sensors three new boronic acids 3, 7 and 11 containing a ferrocene moiety were synthesised. Their design includes an intramolecular B-N bonding motif in order to facilitate binding at physiological pH. We report...

  11. Osmoregulation and acid base regulation of the Asian Horseshoe crab Carcinoscorpius rotundicauda

    Wetter, M.; Cong, N.; Nielsen, Thomas;

    2008-01-01

    to hypercapnia (5% CO2) was partially restored by increased HC = 3-levels in the haemolymph. The degree of compensation did not differ between individuals that had been held at high or low salinity suggesting that the availability of acid-base relevant ions plays a minor role in this response....

  12. Effect of benzoic acid supplementation on acid-base status and mineralmetabolism in catheterized growing pigs

    Nørgaard, Jan Værum; Fernández, José Adalberto; Sørensen, Kristina Ulrich;

    2010-01-01

    Benzoic acid (BA) in diets for growing pigs results in urinary acidification and reduced ammonia emission. The objective was to study the impact of BA supplementation on the acid-base status and mineral metabolism in pigs. Eight female 50-kg pigs, fitted with a catheter in the abdominal aorta, were...

  13. Determining surface areas of marine alga cells by acid-base titration method.

    Wang, X; Ma, Y; Su, Y

    1997-09-01

    A new method for determining the surface area of living marine alga cells was described. The method uses acid-base titration to measure the surface acid/base amount on the surface of alga cells and uses the BET (Brunauer, Emmett, and Teller) equation to estimate the maximum surface acid/base amount, assuming that hydrous cell walls have carbohydrates or other structural compounds which can behave like surface Brönsted acid-base sites due to coordination of environmental H2O molecules. The method was applied to 18 diverse alga species (including 7 diatoms, 2 flagellates, 8 green algae and 1 red alga) maintained in seawater cultures. For the species examined, the surface areas of individual cells ranged from 2.8 x 10(-8) m2 for Nannochloropsis oculata to 690 x 10(-8) m2 for Dunaliella viridis, specific surface areas from 1,030 m2.g-1 for Dunaliella salina to 28,900 m2.g-1 for Pyramidomonas sp. Measurement accuracy was 15.2%. Preliminary studies show that the method may be more promising and accurate than light/electron microscopic measurements for coarse estimation of the surface area of living algae. PMID:9297794

  14. Analysis and Identification of Acid-Base Indicator Dyes by Thin-Layer Chromatography

    Clark, Daniel D.

    2007-01-01

    Thin-layer chromatography (TLC) is a very simple and effective technique that is used by chemists by different purposes, including the monitoring of the progress of a reaction. TLC can also be easily used for the analysis and identification of various acid-base indicator dyes.

  15. Isoelectric Point, Electric Charge, and Nomenclature of the Acid-Base Residues of Proteins

    Maldonado, Andres A.; Ribeiro, Joao M.; Sillero, Antonio

    2010-01-01

    The main object of this work is to present the pedagogical usefulness of the theoretical methods, developed in this laboratory, for the determination of the isoelectric point (pI) and the net electric charge of proteins together with some comments on the naming of the acid-base residues of proteins. (Contains 8 figures and 4 tables.)

  16. Effects of changes in acid base and calcium concentration on fasting serum insulin, proinsulin, and glucose concentrations.

    Smellie, W S; O'Donnell, J; Davidson, H.; Couper, J; Logue, F. C.

    1994-01-01

    AIMS--To test the hypothesis that alterations in acid base or calcium concentration may affect proinsulin processing or the insulin secretion mechanism. METHODS--Changes in proinsulin secretion or cleavage were assessed by measuring serum intact proinsulin and immunoreactive insulin concentrations in three models of acid base and calcium disturbance: (1) subacute changes in acid base status in six volunteers who received oral placebo, ammonium chloride, or sodium bicarbonate for three five da...

  17. Protonation Equilibrium of Linear Homopolyacids

    Požar J.

    2015-07-01

    Full Text Available The paper presents a short summary of investigations dealing with protonation equilibrium of linear homopolyacids, in particularly those of high charge density. Apart from the review of experimental results which can be found in the literature, a brief description of theoretical models used in processing the dependence of protonation constants on monomer dissociation degree and ionic strength is given (cylindrical model based on Poisson-Boltzmann equation, cylindrical Stern model, the models according to Ising, Högfeldt, Mandel and Katchalsky. The applicability of these models regarding the polyion charge density, electrolyte concentration and counterion type is discussed. The results of Monte Carlo simulations of protonation equilibrium are also briefly mentioned. In addition, frequently encountered errors connected with calibration of of glass electrode and the related unreliability of determined protonation constants are pointed out.

  18. Thermal Equilibrium Calorimeters -- An Introduction

    McCammon, D

    2005-01-01

    Near-equilibrium thermal detectors operate as classical calorimeters, with energy deposition and internal equilibration times short compared to the thermal time constant of the device. Advances in fabrication techniques, cryogenics, and electronics have made it practical to measure deposited energy with unprecedented sensitivity and precision. In this chapter we discuss performance considerations for these devices, including optimal filtering and energy resolution calculations. We begin with the basic theory of simple equilibrium calorimeters with ideal resistive thermometers. This provides a starting point for a brief discussion of electrothermal feedback, other noise sources, various non-ideal effects, and nonlinearity. We then describe other types of thermometers and show how they fit into this theoretical framework and why they may require different optimizations and figures of merit. Most of this discussion is applicable also to power detectors, or bolometers, where the detector time constants may be sho...

  19. Equilibrium Corporate Finance and Intermediation

    Bisin, Alberto; Gottardi, Piero; Ruta, Guido

    2014-01-01

    This paper analyzes a class of competitive economies with production, incomplete financial markets, and agency frictions. Firms take their production, financing, and contractual decisions so as to maximize their value under rational conjectures. We show that competitive equilibria exist and that shareholders always unanimously support firms' choices. In addition, equilibrium allocations have well-defined welfare properties: they are constrained efficient when information is symmetric, or when...

  20. Essays on equilibrium policy analysis.

    Gallipoli, G.

    2007-01-01

    This thesis describes and implements a method to carry out policy analysis within an equilibrium framework. This method allows to account for potential effects induced by price adjustments. The analysis is based on overlapping generation, life-cycle models where heterogeneous agents make endogenous decisions regarding their consumption and education as well as labour supply and criminal activity. Some of the agent's optimising decisions (education, crime) are discrete choices. The first part ...

  1. Holding Costs and Equilibrium Arbitrage

    Tuckman, Bruce; Vila, Jean-Luc.

    1993-01-01

    This paper constructs a dynamic model of the equilibrium determination of relative prices when arbitragers face holding costs. The major findings are that 1) models based on riskless arbitrage arguments alone may not provide usefully tight bounds on observed prices, 2) arbitragers are often most effective in eliminating the mispricings of shorter-term assets, 3) arbitrage activity increases the mean reversion of changes in the mispricing process and reduces their conditional volatility, and 4...

  2. Credit segmentation in general equilibrium

    Cea-Echenique, Sebastián; Torres-Martínez, Juan Pablo

    2015-01-01

    We build a general equilibrium model with endogenous borrowing constraints compatible with credit segmentation. There are personalized trading restrictions connecting prices with both portfolio constraints and consumption possibilities, a setting which has not thoroughly been addressed by the literature. Our approach is general enough to be compatible with incomplete market economies where there exist wealth-dependent and/or investment-dependent credit access, borrowing constraints precluding...

  3. On Equilibrium in Monopolistic Competition

    Richard Carson

    2006-01-01

    The price, output, and quality of a monopolistic competitor are determined by maximizing the difference between its revenue and its cost, where cost is measured exclusive of the rent on its product-specialized inputs. It can be argued that such a firm must have unique inputs that are specialized to its unique product—since product differentiation is otherwise compatible with perfect competition—and the uniqueness of these inputs allows them to earn positive rent, even in long-run equilibrium....

  4. Credit Risk in General Equilibrium

    Eichberger, Jürgen; Rheinberger, Klaus; Summer, Martin

    2011-01-01

    Credit risk models used in quantitative risk management treat credit risk analysis conceptually like a single person decision problem. From this perspective an exogenous source of risk drives the fundamental parameters of credit risk: probability of default, exposure at default and the recovery rate. In reality these parameters are the result of the interaction of many market participants: They are endogenous. We develop a general equilibrium model with endogenous credit risk that can be view...

  5. Internal Labor Markets in Equilibrium

    Timothy N. Bond

    2011-01-01

    Traditional models of promotion have difficulty explaining why many firms do not favor internal employees for advancement. I develop a new model to explain this phenomenon. My model generates an equilibrium where some, but not all, ex ante identical firms recruit strictly internally. These firms employ higher quality entry-level workers, since they hire supervisors exclusively from their lower ranks. The scarcity of high-quality workers limits the use of this strategy. I derive several testab...

  6. Essays on equilibrium unemployment dynamics

    Speigner, Bradley James

    2012-01-01

    This thesis is a collection of three essays in which the behaviour of unemployment is studied in different dynamic environments. Throughout, unemployment is understood to be involuntary, arising due to the uncoordinated nature of trade in the labour market as viewed from the perspective of the Diamond-Mortensen-Pissarides equilibrium matching model. It goes without saying that the fundamental motivation for pursuing this line of research is provided by the untold consequences, bot...

  7. An introduction to equilibrium thermodynamics

    Morrill, Bernard; Hartnett, James P; Hughes, William F

    1973-01-01

    An Introduction to Equilibrium Thermodynamics discusses classical thermodynamics and irreversible thermodynamics. It introduces the laws of thermodynamics and the connection between statistical concepts and observable macroscopic properties of a thermodynamic system. Chapter 1 discusses the first law of thermodynamics while Chapters 2 through 4 deal with statistical concepts. The succeeding chapters describe the link between entropy and the reversible heat process concept of entropy; the second law of thermodynamics; Legendre transformations and Jacobian algebra. Finally, Chapter 10 provides a

  8. Residential Segregation in General Equilibrium

    Bayer, Patrick; McMillan, Robert; Rueben, Kim

    2005-01-01

    This paper studies the causes and consequences of racial segregation using a new general equilibrium model that treats neighborhood compositions as endogenous. The model is estimated using unusually detailed restricted Census microdata covering the entire San Francisco Bay Area, and in combination with a rich array of econometric estimates, serves as a powerful tool for carrying out counterfactual simulations that shed light on the causes and consequences of segregation. In terms of causes, a...

  9. Inventories in dynamic general equilibrium

    Shibayama, Katsuyuki

    2010-01-01

    This article investigates a dynamic general equilibrium model with a stockout constraint, which means that no seller can sell more than the inventories that she has. The model successfully explains two inventory facts; (i) inventory investment is procyclical, and (ii) production is more volatile than sales. The key intuition is that, since inventories and demand are complements in generating sales, the optimal level of inventories is increasing in expected demand. Thus, when demand is expecte...

  10. Acid-base analysis: a critique of the Stewart and bicarbonate-centered approaches.

    Kurtz, Ira; Kraut, Jeffrey; Ornekian, Vahram; Nguyen, Minhtri K

    2008-05-01

    When approaching the analysis of disorders of acid-base balance, physical chemists, physiologists, and clinicians, tend to focus on different aspects of the relevant phenomenology. The physical chemist focuses on a quantitative understanding of proton hydration and aqueous proton transfer reactions that alter the acidity of a given solution. The physiologist focuses on molecular, cellular, and whole organ transport processes that modulate the acidity of a given body fluid compartment. The clinician emphasizes the diagnosis, clinical causes, and most appropriate treatment of acid-base disturbances. Historically, two different conceptual frameworks have evolved among clinicians and physiologists for interpreting acid-base phenomena. The traditional or bicarbonate-centered framework relies quantitatively on the Henderson-Hasselbalch equation, whereas the Stewart or strong ion approach utilizes either the original Stewart equation or its simplified version derived by Constable. In this review, the concepts underlying the bicarbonate-centered and Stewart formulations are analyzed in detail, emphasizing the differences in how each approach characterizes acid-base phenomenology at the molecular level, tissue level, and in the clinical realm. A quantitative comparison of the equations that are currently used in the literature to calculate H(+) concentration ([H(+)]) is included to clear up some of the misconceptions that currently exist in this area. Our analysis demonstrates that while the principle of electroneutrality plays a central role in the strong ion formulation, electroneutrality mechanistically does not dictate a specific [H(+)], and the strong ion and bicarbonate-centered approaches are quantitatively identical even in the presence of nonbicarbonate buffers. Finally, our analysis indicates that the bicarbonate-centered approach utilizing the Henderson-Hasselbalch equation is a mechanistic formulation that reflects the underlying acid-base phenomenology. PMID

  11. Investigation of surfactant mediated acid-base charging of mineral oxide particles dispersed in apolar systems.

    Gacek, Matthew M; Berg, John C

    2012-12-21

    The current work examines the role of acid-base properties on particle charging in apolar media. Manipulating the polarity and magnitude of charge in such systems is of growing interest to a number of applications. A major hurdle to the implementation of this technology is that the mechanism(s) of particle charging remain a subject of debate. The authors previously conducted a study of the charging of a series of mineral oxide particles dispersed in apolar systems that contained the surfactant AOT. It was observed that there was a correlation between the particle electrophoretic mobility and the acid-base nature of the particle, as characterized by aqueous point of zero charge (PZC) or the isoelectric point (IEP). The current study investigates whether or not a similar correlation is observed with other surfactants, namely, the acidic Span 80 and the basic OLOA 11000. This is accomplished by measuring the electrophoretic mobility of a series of mineral oxides that are dispersed in Isopar-L containing various concentrations of either Span 80 or OLOA 11000. The mineral oxides used have PZC values that cover a wide range of pH, providing a systematic study of how particle and surfactant acid-base properties impact particle charge. It was found that the magnitude and polarity of particle surface charge varied linearly with the particle PZC for both surfactants used. In addition, the point at which the polarity of charge reversed for the basic surfactant OLOA 11000 was shifted to a pH of approximately 8.5, compared to the previous result of about 5 for AOT. This proves that both surfactant and particle acid-base properties are important, and provides support for the theory of acid-base charging in apolar media. PMID:23157688

  12. Mesoscopic non-equilibrium thermodynamics

    Rubi, Jose' Miguel

    2008-02-01

    Full Text Available Basic concepts like energy, heat, and temperature have acquired a precise meaning after the development of thermodynamics. Thermodynamics provides the basis for understanding how heat and work are related and with the general rules that the macroscopic properties of systems at equilibrium follow. Outside equilibrium and away from macroscopic regimes most of those rules cannot be applied directly. In this paper we present recent developments that extend the applicability of thermodynamic concepts deep into mesoscopic and irreversible regimes. We show how the probabilistic interpretation of thermodynamics together with probability conservation laws can be used to obtain kinetic equations describing the evolution of the relevant degrees of freedom. This approach provides a systematic method to obtain the stochastic dynamics of a system directly from the knowledge of its equilibrium properties. A wide variety of situations can be studied in this way, including many that were thought to be out of reach of thermodynamic theories, such as non-linear transport in the presence of potential barriers, activated processes, slow relaxation phenomena, and basic processes in biomolecules, like translocation and stretching.

  13. Morphodynamic equilibrium of alluvial estuaries

    Tambroni, Nicoletta; Bolla Pittaluga, Michele; Canestrelli, Alberto; Lanzoni, Stefano; Seminara, Giovanni

    2014-05-01

    The evolution of the longitudinal bed profile of an estuary, with given plan-form configuration, subject to given tidal forcing at the mouth and prescribed values of water and sediment supply from the river is investigated numerically. Our main goal is to ascertain whether, starting from some initial condition, the bed evolution tends to reach a unique equilibrium configuration asymptotically in time. Also, we investigate the morphological response of an alluvial estuary to changes in the tidal range and hydrologic forcing (flow and sediment supply). Finally, the solution helps characterizing the transition between the fluvially dominated region and the tidally dominated region of the estuary. All these issues play an important role also in interpreting how the facies changes along the estuary, thus helping to make correct paleo-environmental and sequence-stratigraphic interpretations of sedimentary successions (Dalrymple and Choi, 2007). Results show that the model is able to describe a wide class of settings ranging from tidally dominated estuaries to fluvially dominated estuaries. In the latter case, the solution is found to compare satisfactory with the analytical asymptotic solution recently derived by Seminara et al. (2012), under the hypothesis of fairly 'small' tidal oscillations. Simulations indicate that the system always moves toward an equilibrium configuration in which the net sediment flux in a tidal cycle is constant throughout the estuary and equal to the constant sediment flux discharged from the river. For constant width, the bed equilibrium profile of the estuarine channel is characterized by two distinct regions: a steeper reach seaward, dominated by the tide, and a less steep upstream reach, dominated by the river and characterized by the undisturbed bed slope. Although the latter reach, at equilibrium, is not directly affected by the tidal wave, however starting from an initial uniform stream with the constant 'fluvial' slope, the final

  14. The Geometry of Finite Equilibrium Datasets

    Balasko, Yves; Tvede, Mich

    We investigate the geometry of finite datasets defined by equilibrium prices, income distributions, and total resources. We show that the equilibrium condition imposes no restrictions if total resources are collinear, a property that is robust to small perturbations. We also show that the set of...... equilibrium datasets is pathconnected when the equilibrium condition does impose restrictions on datasets, as for example when total resources are widely non collinear....

  15. Accelerating Multiagent Reinforcement Learning by Equilibrium Transfer.

    Hu, Yujing; Gao, Yang; An, Bo

    2015-07-01

    An important approach in multiagent reinforcement learning (MARL) is equilibrium-based MARL, which adopts equilibrium solution concepts in game theory and requires agents to play equilibrium strategies at each state. However, most existing equilibrium-based MARL algorithms cannot scale due to a large number of computationally expensive equilibrium computations (e.g., computing Nash equilibria is PPAD-hard) during learning. For the first time, this paper finds that during the learning process of equilibrium-based MARL, the one-shot games corresponding to each state's successive visits often have the same or similar equilibria (for some states more than 90% of games corresponding to successive visits have similar equilibria). Inspired by this observation, this paper proposes to use equilibrium transfer to accelerate equilibrium-based MARL. The key idea of equilibrium transfer is to reuse previously computed equilibria when each agent has a small incentive to deviate. By introducing transfer loss and transfer condition, a novel framework called equilibrium transfer-based MARL is proposed. We prove that although equilibrium transfer brings transfer loss, equilibrium-based MARL algorithms can still converge to an equilibrium policy under certain assumptions. Experimental results in widely used benchmarks (e.g., grid world game, soccer game, and wall game) show that the proposed framework: 1) not only significantly accelerates equilibrium-based MARL (up to 96.7% reduction in learning time), but also achieves higher average rewards than algorithms without equilibrium transfer and 2) scales significantly better than algorithms without equilibrium transfer when the state/action space grows and the number of agents increases. PMID:25181517

  16. Toward the Understanding of the Metabolism of Levodopa I. DFT Investigation of the Equilibrium Geometries, Acid-Base Properties and Levodopa-Water Complexes

    Shabaan A. K. Elroby

    2012-04-01

    Full Text Available Levodopa (LD is used to increase dopamine level for treating Parkinson’s disease. The major metabolism of LD to produce dopamine is decarboxylation. In order to understand the metabolism of LD; the electronic structure of levodopa was investigated at the Density Functional DFT/B3LYP level of theory using the 6-311+G** basis set, in the gas phase and in solution. LD is not planar, with the amino acid side chain acting as a free rotator around several single bonds. The potential energy surface is broad and flat. Full geometry optimization enabled locating and identifying the global minimum on this Potential energy surface (PES. All possible protonation/deprotonation forms of LD were examined and analyzed. Protonation/deprotonation is local in nature, i.e., is not transmitted through the molecular framework. The isogyric protonation/deprotonation reactions seem to involve two subsequent steps: First, deprotonation, then rearrangement to form H-bonded structures, which is the origin of the extra stability of the deprotonated forms. Natural bond orbital (NBO analysis of LD and its deprotonated forms reveals detailed information of bonding characteristics and interactions across the molecular framework. The effect of deprotonation on the donor-acceptor interaction across the molecular framework and within the two subsystems has also been examined. Attempts to mimic the complex formation of LD with water have been performed.

  17. Status Equilibrium for Local Public Good Economies

    Anne van den Nouweland; Myrna H. Wooders

    2005-01-01

    We introduce a concept of status equilibrium for local public good economies. A status equilibrium specifies one status index for each agent in an economy. These indices determine agents' cost shares in any possible jurisdiction to which the agent might belong. We provide an axiomatic charaterization of status equilibrium using consistency properties.

  18. Mathematical Models and Equilibrium in Irreversible Microeconomics

    Anatoly M. Tsirlin; Sergey A. Amelkin

    2010-01-01

    A set of equilibrium states in a system consisting of economic agents, economic reservoirs, and firms is considered. Methods of irreversible microeconomics are used. We show that direct sale/purchase leads to an equilibrium state which depends upon the coefficients of supply/demand functions. To reach the unique equilibrium state it is necessary to add either monetary exchange or an intermediate firm.

  19. Open problems in non-equilibrium physics

    Kusnezov, D.

    1997-09-22

    The report contains viewgraphs on the following: approaches to non-equilibrium statistical mechanics; classical and quantum processes in chaotic environments; classical fields in non-equilibrium situations: real time dynamics at finite temperature; and phase transitions in non-equilibrium conditions.

  20. Risk premia in general equilibrium

    Posch, Olaf

    solutions of dynamic stochastic general equilibrium models, including a novel solution with endogenous labor supply, to obtain closed-form expressions for the risk premium in production economies. We find that the curvature of the policy functions affects the risk premium through controlling the individual......This paper shows that non-linearities can generate time-varying and asymmetric risk premia over the business cycle. These (empirical) key features become relevant and asset market implications improve substantially when we allow for non-normalities in the form of rare disasters. We employ explicit......'s effective risk aversion....

  1. Conformations of Proteins in Equilibrium

    Micheletti, Cristian; Banavar, Jayanth R.; Maritan, Amos

    2001-08-20

    We introduce a simple theoretical approach for an equilibrium study of proteins with known native-state structures. We test our approach with results on well-studied globular proteins, chymotrypsin inhibitor (2ci2), barnase, and the alpha spectrin SH3 domain, and present evidence for a hierarchical onset of order on lowering the temperature with significant organization at the local level even at high temperatures. A further application to the folding process of HIV-1 protease shows that the model can be reliably used to identify key folding sites that are responsible for the development of drug resistance.

  2. Equilibrium emission of nuclear fragments

    In the present paper data are presented which demonstrate that for IMF production the use of intermediate energy heavy-ion-induced reactions at energies of 15-30 MeV/nucleon is extremely tenuous due to the possibility of contributions from deep inelastic collisions, fission and from preequilibrium mechanisms. Furthermore it is argued that the apparent temperatures extracted from the slopes of the fragment energy spectra correlate with the reaction variables in a manner which is more consistent with pre-equilibrium emission in the spirit of the exciton model, instead of a spatially localized thermal excitation or a 'hot spot'. (orig./BBOE)

  3. Spectroscopic study on variations in illite surface properties after acid-base titration

    2003-01-01

    FT-IR, Raman microscopy, XRD, 29 Si and 27 Al MAS NMR, were used to investigate changes in surface properties of a natural illitesample after acid-base potentiometric titration. The characteristic XRD lines indicated the presence of surface Al-Si complexes, preferable to Al(OH)3 precipitates. In the microscopic Raman spectra, the vibration peaks of Si-O and Al-O bonds diminished as a result of treatment withacid, then increased after hydroxide back titration. The varied ratio of signal intensity between Ⅳ Al and Ⅵ At species in 27 Al MAS NMRspectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure ofillite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illitesurfaces and acid-leaching silicic acid and aluminum ions should be considered in the model description of surface acid-base properties of theaqueous illite.

  4. Acid-Base Behavior in Hydrothermal Processing of Wastes - Final Report

    A major obstacle to development of hydrothermal oxidation technology has been a lack of scientific knowledge of chemistry in hydrothermal solution above 350 C, particularly acid-base behavior, and transport phenomena, which is needed to understand corrosion, metal-ion complexation, and salt precipitation and recovery. Our objective has been to provide this knowledge with in situ UV-visible spectroscopic measurements and fully molecular computer simulation. Our recent development of relatively stable organic UV-visible pH indicators for supercritical water oxidation offers the opportunity to characterize buffers and to monitor acid-base titrations. These results have important implications for understanding reaction pathways and yields for decomposition of wastes in supercritical water

  5. Hyperventilation and blood acid-base balance in hypercapnia exposed red drum (Sciaenops ocellatus).

    Ern, Rasmus; Esbaugh, Andrew J

    2016-05-01

    Hyperventilation is a common response in fish exposed to elevated water CO2. It is believed to lessen the respiratory acidosis associated with hypercapnia by lowering arterial PCO2, but the contribution of hyperventilation to blood acid-base compensation has yet to be quantified. Hyperventilation may also increase the flux of irons across the gill epithelium and the cost of osmoregulation, owing to the osmo-respiratory compromise. Therefore, hypercapnia exposed fish may increase standard metabolic rate (SMR) leaving less energy for physiological functions such as foraging, migration, growth and reproduction. Here we show that gill ventilation, blood PCO2 and total blood [CO2] increased in red drum (Sciaenops ocellatus) exposed to 1000 and 5000 µatm water CO2, and that blood PCO2 and total blood [CO2] decrease in fish during hypoxia induced hyperventilation. Based on these results we estimate the ventilatory contributions to total acid-base compensation in 1000 and 5000 µatm water CO2. We find that S. ocellatus only utilize a portion of its ventilatory capacity to reduce the acid-base disturbance in 1000 µatm water CO2. SMR was unaffected by both salinity and hypercapnia exposure indicating that the cost of osmoregulation is small relative to SMR, and that the lack of increased ventilation in 1000 µatm water CO2 despite the capacity to do so is not due to an energetic tradeoff between acid-base balance and osmoregulation. Therefore, while ocean acidification may impact ventilatory parameters, there will be little impact on the overall energy budget of S. ocellatus. PMID:26922790

  6. Determination of low citric acid concentrations in a mixture of weak acid/bases

    Lahav, O.; Shlafman, E.; Cochva, M.

    2005-01-01

    A titration approach was developed to measure low concentrations of citric acid (C6H8O7) in a mixture of other weak acid/ bases. Two methods were tested. The first and more practical method (a 4-point titration procedure) is applicable in conditions where volatile fatty acids (VFAs) are not normally present. The second method (a 5-point titration procedure) was developed for anaerobic environments where VFAs may be encountered. Generally, fairly accurate and repetitive results (precision > 95...

  7. Acid-Base Pairs in Lewis Acidic Zeolites Promote Direct Aldol Reactions by Soft Enolization.

    Lewis, Jennifer D; Van de Vyver, Stijn; Román-Leshkov, Yuriy

    2015-08-17

    Hf-, Sn-, and Zr-Beta zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions. PMID:26138135

  8. Real-Time Detection of Deoxyribonucleic Acid Bases via their Negative Differential Conductance Signature

    Dragoman, Daniela; Dragoman, Mircea

    2009-01-01

    In this paper we present a method for the real-time detection of the bases of the deoxyribonucleic acid using their signatures in negative differential conductance measurements. The present methods of electronic detection of deoxyribonucleic acid bases are based on a statistical analysis because the electrical currents of the four bases are weak and do not differ significantly from one base to another. In contrast, we analyze a device that combines the accumulated knowledge in nanopore and sc...

  9. Synthesis and Properties of Lactic Acid-based Cross-linked Poly(ester-amide)

    Yue Ying HE; Cong Ming XIAO

    2006-01-01

    A novel lactic acid-based cross-linked poly(ester-amide) (LCPEA) was synthesized. The gel fraction of the LCPEA could be modulated by the reaction conditions and it affected the mechanical and thermal properties of the LCPEA. The tensile strength, elastic modulus and bend strength of the LCPEA of 65% gel fraction were 4.65, 136.55 and 39.63 MPa, respectively. The thermal decomposition temperature (50 wt%) of the LCPEA was around 410 ℃.

  10. Acid-base and electrolyte disorders in patients with diabetes mellitus

    Nikolaos Sotirakopoulos

    2012-01-01

    Full Text Available Diabetes mellitus is the most common metabolic disorder in the community. The diabetics may suffer from acid-base and electrolyte disorders due to complications of diabetes mellitus and the medication they receive. In this study, acid-base and electrolyte disorders were evaluated among outpatient diabetics in our hospital. The study consisted of patients with diabetes mellitus who visited the hospital as outpatients between the period January 1, 2004 to December 31, 2006. The patients′ medical history, age and type of diabetes were noted, including whether they were taking diuretics and calcium channel blockers or not. Serum creatinine, proteins, sodium, potassium and chloride and blood gases were measured in all patients. Proteinuria was measured by 24-h urine collection. Two hundred and ten patients were divided in three groups based on the serum creatinine. Group A consisted of 114 patients that had serum creatinine 3.1 mg/dL. Of the 210 patients, 176 had an acid-base disorder. The most common disorder noted in group A was metabolic alkalosis. In groups B and C, the common disorders were metabolic acidosis and alkalosis, and metabolic acidosis, respectively. The most common electrolyte disorders were hypernatremia (especially in groups A and B, hyponatremia (group C and hyperkalemia (especially in groups B and C. It is concluded that: (a in diabetic outpatients, acid-base and electrolyte disorders occurred often even if the renal function is normal, (b the most common disorders are metabolic alkalosis and metabolic acidosis (the frequency increases with the deterioration of the renal function and (c the common electrolyte disorders are hypernatremia and hypokalemia.

  11. Biodiesel Production from Spent Fish Frying Oil Through Acid-Base Catalyzed Transesterification

    Abdalrahman B. Fadhil; Mohammed M. Dheyab; Kareem M. Ahmed; Marwa H. Yahya

    2012-01-01

    Biodiesel fuels were prepared from a special type of frying oil namely spent fish frying oil through two step transesterification viz. acid-base catalyzed transesterification. Hydrochloric acid and potassium hydroxide with methanol were used for this purpose. The oil was pre-treated with (1.0 wt% HCl) and methanol to reduce free fatty acids content of the oil. Then, conditions of the base catalyzed step such as base concentration, reaction temperature, methanol to oil molar ratio and reaction...

  12. Departures from Local Thermodynamic Equilibrium

    This paper starts with a definition of local thermodynamic equilibrium and points out the relationship between local and complete thermodynamic equilibrium. It is shown that electron collisions are essential for the establishment of LTE and a relationship is derived for the minimum electron density at which collision processes are just sufficiently frequent to cause the plasma to be in LTE in face of the competing radiative processes. This relationship is derived for an optically thin plasma. The effect of radiation trapping is considered and some figures given by which the effect of this can be taken into account in assessing the validity of LTE in such cases. Account is now taken of the finite time required for the atomic collision processes to establish the plasma in LTE. A numerical example is worked out which shows that these considerations can be very important for plasmas of rapidly varying temperature. Mention is also made of departures from LTE caused by inhomogeneities in the plasma and by the positive ions having a different kinetic temperature from the electrons. Finally, it is remarked that even if the criteria for LTE to be valid are not met then the Saha and Boltzmann equations may still be applied to describe the population densities of the upper levels of individual species of atoms or ions. (author)

  13. Pre-equilibrium plasma dynamics

    Approaches towards understanding and describing the pre-equilibrium stage of quark-gluon plasma formation in heavy-ion collisions are reviewed. Focus is on a kinetic theory approach to non-equilibrium dynamics, its extension to include the dynamics of color degrees of freedom when applied to the quark-gluon plasma, its quantum field theoretical foundations, and its relationship to both the particle formation stage at the very beginning of the nuclear collision and the hydrodynamic stage at late collision times. The usefulness of this approach to obtain the transport coefficients in the quark-gluon plasma and to derive the collective mode spectrum and damping rates in this phase are discussed. Comments are made on the general difficulty to find appropriated initial conditions to get the kinetic theory started, and a specific model is given that demonstrates that, once given such initial conditions, the system can be followed all the way through into the hydrodynamical regime. 39 refs., 7 figs

  14. NaVirCept - Nucleic Acid-Based Anti-Viral Project

    Vaccines are generally considered to be the most effective countermeasures to bacterial and viral diseases, however, licensed vaccines against many disease agents are either not available or their efficacies have not been demonstrated. Vaccines are generally agent specific in terms of treatment spectrum and are subject to defeat through natural mutation or through directed efforts. With respect to viral therapeutics, one of the major limitations associated with antiviral drugs is acquired drug resistance caused by antigenic shift or drift. A number of next-generation prophylactic and/or therapeutic measures are on the horizon. Of these, nucleic acid-based drugs are showing great antiviral potential. These drugs elicit long-lasting, broad spectrum protective immune responses, especially to respiratory viral pathogens. The Nucleic Acid-Based Antiviral (NaVirCept) project provides the opportunity to demonstrate the effectiveness of novel medical countermeasures against military-significant endemic and other viral threat agents. This project expands existing DRDC drug delivery capability development, in the form of proprietary liposome intellectual property, by coupling it with leading-edge nucleic acid-based technology to deliver effective medical countermeasures that will protect deployed personnel and the warfighter against a spectrum of viral disease agents. The technology pathway will offer a means to combat emerging viral diseases or modified threat agents such as the bird flu or reconstructed Spanish flu without going down the laborious, time-consuming and expensive paths to develop countermeasures for each new and/or emerging viral disease organism.(author)

  15. Aqueous extracts of Mozambican plants as alternative and environmentally safe acid-base indicators.

    Macuvele, Domingos Lusitaneo Pier; Sithole, Gerre Zebedias Samo; Cesca, Karina; Macuvele, Suzana Lília Pinare; Matsinhe, Jonas Valente

    2016-06-01

    Indicators are substances that change color as the pH of the medium. Many of these substances are dyes of synthetic origin. The mulala plant (Euclea natalensis), which roots are commonly used by rural communities for their oral hygiene, and roseira (Hibiscus rosa-sinensis), an ornamental plant, are abundant in Mozambique. Currently, synthetic acid-base indicators are most commonly used but have environmental implications and, on the other hand, are expensive products, so the demand for natural indicators started. This study investigated the applicability of aqueous extracts of H. rosa-sinensis and E. natalensis as acid-base indicators. Ground on this work, the extracts can be used as acid-base indicators. On the basis of the absorption spectroscopy in both the UV-Vis region and previous studies, it was possible to preliminarily pinpoint anthocyanins and naphthoquinones as responsible for the shifting of colors depending on the pH range of aqueous extracts of H. rosa-sinensis and E. natalensis. These natural indicators are easily accessible, inexpensive, easy to extract, environmentally safe, and locally available. PMID:26936478

  16. Equilibrium structure of ferrofluid aggregates

    We study the equilibrium structure of large but finite aggregates of magnetic dipoles, representing a colloidal suspension of magnetite particles in a ferrofluid. With increasing system size, the structural motif evolves from chains and rings to multi-chain and multi-ring assemblies. Very large systems form single- and multi-wall coils, tubes and scrolls. These structural changes result from a competition between various energy terms, which can be approximated analytically within a continuum model. We also study the effect of external parameters such as magnetic field on the relative stability of these structures. Our results may give insight into experimental data obtained during solidification of ferrofluid aggregates at temperatures where thermal fluctuations become negligible in comparison to inter-particle interactions. These data may also help to experimentally control the aggregation of magnetic particles.

  17. Ringed accretion disks: equilibrium configurations

    Pugliese, D

    2015-01-01

    We investigate a model of ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the General Relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can be then determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We pr...

  18. Hierarchical condensation near phase equilibrium

    Olemskoi, A. I.; Yushchenko, O. V.; Borisyuk, V. N.; Zhilenko, T. I.; Kosminska, Yu. O.; Perekrestov, V. I.

    2012-06-01

    A novel mechanism of new phase formation is studied both experimentally and theoretically in the example of quasi-equilibrium stationary condensation in an ion-plasma sputterer. Copper condensates are obtained to demonstrate that a specific network structure is formed as a result of self-assembly in the course of deposition. The fractal pattern related is inherent in the phenomena of diffusion limited aggregation. Condensate nuclei are shown to form statistical ensemble of hierarchically subordinated objects distributed in ultrametric space. The Langevin equation and the Fokker-Planck equation related are found to describe stationary distribution of thermodynamic potential variations at condensation. Time dependence of the formation probability of branching structures is found to clarify the experimental situation.

  19. Equilibrium Analysis in Cake Cutting

    Branzei, Simina; Miltersen, Peter Bro

    2013-01-01

    Cake cutting is a fundamental model in fair division; it represents the problem of fairly allocating a heterogeneous divisible good among agents with different preferences. The central criteria of fairness are proportionality and envy-freeness, and many of the existing protocols are designed to...... guarantee proportional or envy-free allocations, when the participating agents follow the protocol. However, typically, all agents following the protocol is not guaranteed to result in a Nash equilibrium. In this paper, we initiate the study of equilibria of classical cake cutting protocols. We consider one...... of the simplest and most elegant continuous algorithms -- the Dubins-Spanier procedure, which guarantees a proportional allocation of the cake -- and study its equilibria when the agents use simple threshold strategies. We show that given a cake cutting instance with strictly positive value density...

  20. Equilibrium size distribution of rouleaux

    Perelson, A.S. (Los Alamos National Lab., NM); Wiegel, F.W.

    1982-02-01

    Rouleaux are formed by the aggregation of red blood cells in the presence of macromolecules that bridge the membranes of adherent erythrocytes. We compute the size and degree of branching of rouleaux for macroscopic systems in thermal equilibrium in the absence of fluid flow. Using techniques from statistical mechanics, analytical expressions are derived for (a) the average number of rouleaux consisting of n cells and having m branch points; (b) the average number of cells per rouleau; (c) the average number of branch points per rouleau; and (d) the number of rouleaux with n cells, n = 1, 2,..., in a system containing a total of N cells. We also present the results of numerical evaluations to establish the validity of asymptotic expressions that simplify our formal analytic results.

  1. A Constructive Generalization of Nash Equilibrium

    Huang, Xiaofei

    2009-01-01

    In a society of multiple individuals, if everybody is only interested in maximizing his own payoff, will there exist any equilibrium for the society? John Nash proved more than 50 years ago that an equilibrium always exists such that nobody would benefit from unilaterally changing his strategy. Nash Equilibrium is a central concept in game theory, which offers the mathematical foundation for social science and economy. However, the original definition is declarative without including a solution to find them. It has been found later that it is computationally difficult to find a Nash equilibrium. Furthermore, a Nash equilibrium may be unstable, sensitive to the smallest variation of payoff functions. Making the situation worse, a society with selfish individuals can have an enormous number of equilibria, making it extremely hard to find out the global optimal one. This paper offers a constructive generalization of Nash equilibrium to cover the case when the selfishness of individuals are reduced to lower level...

  2. Nash Equilibrium in Generalised Muller Games

    Paul, Soumya; Simon, Sunil

    2009-01-01

    We suggest that extending Muller games with preference ordering for players is a natural way to reason about unbounded duration games. In this context, we look at the standard solution concept of Nash equilibrium for non-zero sum games. We show that Nash equilibria always exists for such generalised Muller games on finite graphs and present a procedure to compute an equilibrium strategy profile. We also give a procedure to compute a subgame perfect equilibrium when it exi...

  3. A General Equilibrium Approach of Retail Payments

    Tamás Ilyés; Lóránt Varga

    2015-01-01

    In our paper, we introduce the Hungarian Payment System Model (HUPS), a computable general equilibrium model with detailed payment services which can be used for policy evaluation and forecast. In the last years, several studies investigated different aspects of payment systems and some papers used equilibrium theory to study a specific segment or question of retail payments. In our paper, we take a step forward as we extend this research using the general equilibrium approach. The HUPS model...

  4. Mathematical models and equilibrium in irreversible microeconomics

    Anatoly M. Tsirlin

    2010-07-01

    Full Text Available A set of equilibrium states in a system consisting of economic agents, economic reservoirs, and firms is considered. Methods of irreversible microeconomics are used. We show that direct sale/purchase leads to an equilibrium state which depends upon the coefficients of supply/demand functions. To reach the unique equilibrium state it is necessary to add either monetary exchange or an intermediate firm.

  5. Equilibrium in CAPM without a Riskless Asset.

    Nielsen, Lars Tyge

    1990-01-01

    In the mean-variance capital asset pricing model without a riskless asset, the possibility of satiation sometimes leads to nonexistence of general equilibrium. Moreover, because portfolio preferences are not necessarily monotone, equilibrium asset prices, when they exist, may be negative or zero. To demonstrate the possibility of nonexistence, and to develop an intuitive understanding of when and why equilibrium does or does not exist, this paper fully investigates the special case of utility...

  6. Coarse Competitive Equilibrium and Extreme Prices

    Faruk Gul; Wolfgang Pesendorfer; Tomasz Strzalecki

    2014-01-01

    We introduce a notion of coarse competitive equilibrium (CCE), to study agents' inability to tailor their consumption to the state of the economy. Our notion is motivated by limited cognitive ability (in particular attention, memory, and complexity) and it maintains the complete market structure of competitive equilibrium. Compared to standard competitive equilibrium, our concept yields riskier allocations and more extreme prices. We provide a tractable model that is suitable for general equi...

  7. Seasonality and equilibrium business cycle theories

    R. Anton Braun; Evans, Charles L.

    1991-01-01

    Barksy-Miron [1989] find that the postwar U.S. economy exhibits a regular seasonal cycle, as well as the business cycle phenomenon. Are these findings consistent with current equilibrium business cycle theories as surveyed by Prescott [1986]? We consider a dynamic, stochastic equilibrium business cycle model which includes deterministic seasonals and nontime-separable preferences. We show how to compute a perfect foresight seasonal equilibrium path for this economy. An approximation to the st...

  8. Synthesis, characterization and catalytic activity of acid-base bifunctional materials through protection of amino groups

    Shao, Yanqiu [College of Chemistry, Jilin University, Changchun 130023 (China); College of Chemistry, Mudanjiang Normal University, Mudanjiang 157012 (China); Liu, Heng; Yu, Xiaofang [College of Chemistry, Jilin University, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@mail.jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130023 (China)

    2012-03-15

    Graphical abstract: Acid-base bifunctional mesoporous material SO{sub 3}H-SBA-15-NH{sub 2} was successfully synthesized under low acidic medium through protection of amino groups. Highlights: Black-Right-Pointing-Pointer The acid-base bifunctional material SO{sub 3}H-SBA-15-NH{sub 2} was successfully synthesized through protection of amino groups. Black-Right-Pointing-Pointer The obtained bifunctional material was tested for aldol condensation. Black-Right-Pointing-Pointer The SO{sub 3}H-SBA-15-NH{sub 2} catalyst containing amine and sulfonic acid groups exhibited excellent acid-basic properties. -- Abstract: Acid-base bifunctional mesoporous material SO{sub 3}H-SBA-15-NH{sub 2} was successfully synthesized under low acidic medium through protection of amino groups. X-ray diffraction (XRD), N{sub 2} adsorption-desorption, transmission electron micrographs (TEM), back titration, {sup 13}C magic-angle spinning (MAS) NMR and {sup 29}Si magic-angle spinning (MAS) NMR were employed to characterize the synthesized materials. The obtained bifunctional material was tested for aldol condensation reaction between acetone and 4-nitrobenzaldehyde. Compared with monofunctional catalysts of SO{sub 3}H-SBA-15 and SBA-15-NH{sub 2}, the bifunctional sample of SO{sub 3}H-SBA-15-NH{sub 2} containing amine and sulfonic acid groups exhibited excellent acid-basic properties, which make it possess high activity for the aldol condensation.

  9. Synthesis of acid-base bifunctional mesoporous materials by oxidation and thermolysis

    Yu, Xiaofang [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Zou, Yongcun [State Key Laboratory of Inoranic Synthesis and Preparative Chemistryg, College of Chemistry, Jilin University, Changchun 130012 (China); Wu, Shujie; Liu, Heng [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Guan, Jingqi, E-mail: guanjq@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China); Kan, Qiubin, E-mail: qkan@jlu.edu.cn [College of Chemistry, Jilin University, Jiefang Road 2519, Changchun 130023 (China)

    2011-06-15

    Graphical abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst. The obtained sample of SO{sub 3}H-MCM-41-NH{sub 2} containing amine and sulfonic acids exhibits excellent catalytic activity in aldol condensation reaction. Research highlights: {yields} Synthesize acid-base bifunctional mesoporous materials SO{sub 3}H-MCM-41-NH{sub 2}. {yields} Oxidation and then thermolysis to generate acidic site and basic site. {yields} Exhibit good catalytic performance in aldol condensation reaction between acetone and various aldehydes. -- Abstract: A novel and efficient method has been developed for the synthesis of acid-base bifunctional catalyst SO{sub 3}H-MCM-41-NH{sub 2}. This method was achieved by co-condensation of tetraethylorthosilicate (TEOS), 3-mercaptopropyltrimethoxysilane (MPTMS) and (3-triethoxysilylpropyl) carbamicacid-1-methylcyclohexylester (3TAME) in the presence of cetyltrimethylammonium bromide (CTAB), followed by oxidation and then thermolysis to generate acidic site and basic site. X-ray diffraction (XRD) and transmission electron micrographs (TEM) show that the resultant materials keep mesoporous structure. Thermogravimetric analysis (TGA), X-ray photoelectron spectra (XPS), back titration, solid-state {sup 13}C CP/MAS NMR and solid-state {sup 29}Si MAS NMR confirm that the organosiloxanes were condensed as a part of the silica framework. The bifunctional sample (SO{sub 3}H-MCM-41-NH{sub 2}) containing amine and sulfonic acids exhibits excellent acid-basic properties, which make it possess high activity in aldol condensation reaction between acetone and various aldehydes.

  10. 1-D EQUILIBRIUM DISCRETE DIFFUSION MONTE CARLO

    T. EVANS; ET AL

    2000-08-01

    We present a new hybrid Monte Carlo method for 1-D equilibrium diffusion problems in which the radiation field coexists with matter in local thermodynamic equilibrium. This method, the Equilibrium Discrete Diffusion Monte Carlo (EqDDMC) method, combines Monte Carlo particles with spatially discrete diffusion solutions. We verify the EqDDMC method with computational results from three slab problems. The EqDDMC method represents an incremental step toward applying this hybrid methodology to non-equilibrium diffusion, where it could be simultaneously coupled to Monte Carlo transport.

  11. Determining Equilibrium Position For Acoustical Levitation

    Barmatz, M. B.; Aveni, G.; Putterman, S.; Rudnick, J.

    1989-01-01

    Equilibrium position and orientation of acoustically-levitated weightless object determined by calibration technique on Earth. From calibration data, possible to calculate equilibrium position and orientation in presence of Earth gravitation. Sample not levitated acoustically during calibration. Technique relies on Boltzmann-Ehrenfest adiabatic-invariance principle. One converts resonant-frequency-shift data into data on normalized acoustical potential energy. Minimum of energy occurs at equilibrium point. From gradients of acoustical potential energy, one calculates acoustical restoring force or torque on objects as function of deviation from equilibrium position or orientation.

  12. Acid-base thermochemistry of gaseous oxygen and sulfur substituted amino acids (Ser, Thr, Cys, Met)

    Riffet, Vanessa; Frison, Gilles; Bouchoux, Guy

    2011-01-01

    Acid-base thermochemistry of isolated amino acids containing oxygen or sulfur in their side chain (serine, threonine, cysteine and methionine) have been examined by quantum chemical computations. Density functional theory (DFT) was used, with B3LYP, B97-D and M06-2X functionals using the 6-31+G(d,p) basis set for geometry optimizations and the larger 6-311++G(3df,2p) basis set for energy computations. Composite methods CBS-QB3, G3B3, G4MP2 and G4 were applied to large sets of neutral, protona...

  13. The role of gelatin in a methacrylic acid based gel dosimeter

    In this work, the dose response of a methacrylic acid based gel dosimeter containing different concentrations of gelatin is examined to clarify the role of gelatin in the polymerization process. Direct temperature monitoring of the gel throughout the irradiation process is adopted as the method. In addition, to investigate the function of gelatin on polymerization, another experiments are performed after replacing gelatin with some acids. From the results, it is concluded that gelatin is an indispensable component in the polymerization reaction which acts as a 'trigger', and that the peptide structure in gelatin also assumes an important role.

  14. Determination of the acidic sites of purified single-walled carbon nanotubes by acid base titration

    Hu, H.; Bhowmik, P.; Zhao, B.; Hamon, M. A.; Itkis, M. E.; Haddon, R. C.

    2001-09-01

    We report the measurement of the acidic sites in three different samples of commercially available full-length purified single-walled carbon nanotubes (SWNTs) - as obtained from CarboLex (CLI), Carbon Solutions (CSI) and Tubes@Rice (TAR) - by simple acid-base titration methods. Titration of the purified SWNTs with NaOH and NaHCO 3 solutions was used to determine the total percentage of acidic sites and carboxylic acid groups, respectively. The total percentage of acidic sites in full length purified SWNTs from TAR, CLI and CSI are about 1-3%.

  15. Has Stewart approach improved our ability to diagnose acid-base disorders in critically ill patients?

    Masevicius, Fabio D; Dubin, Arnaldo

    2015-01-01

    The Stewart approach-the application of basic physical-chemical principles of aqueous solutions to blood-is an appealing method for analyzing acid-base disorders. These principles mainly dictate that pH is determined by three independent variables, which change primarily and independently of one other. In blood plasma in vivo these variables are: (1) the PCO2; (2) the strong ion difference (SID)-the difference between the sums of all the strong (i.e., fully dissociated, chemically nonreacting...

  16. Acid-base properties of the surface of InSb-CdTe solid solutions

    Acid-base properties of the surface of solid solutions and binary components of the InSb-CdTe system are studied using IR spectroscopy, conductometric titration, and measuring the pH-isoelectric state upon treating the test samples by evacuation under atmospheric conditions, exposure to gases (NO2, NH3) and γ radiation. The nature, strength, and concentration of acid centers are determined. Variation in the concentration of acid centers is evaluated as a function of the above factors and changes in the composition of the system

  17. FERTILIZATION OF VINE BY A 5-AMINOLEVULINIC ACID-BASED FERTILIZER AND ITS PROFITABILITY

    VLADIMR IMANSK; Otto LOEK

    2013-01-01

    In this work we investigated the effect of different doses of NPKS fertilizer added into the soil for nutrient contents in the soil, as well as the quantity and quality of grapes. During the vegetation of the vine, we tested the 5-aminolevulinic acid-based fertilizer (ALA). We summarize that higher doses of fertilizer added into soil caused higher amounts of available nutrients. During the vegetation of the vine an increase of ALA had a positive effect on the optimal balance of nutrients. Fer...

  18. Relationship of students' conceptual representations and problem-solving abilities in acid-base chemistry

    Powers, Angela R.

    2000-10-01

    This study explored the relationship between secondary chemistry students' conceptual representations of acid-base chemistry, as shown in student-constructed concept maps, and their ability to solve acid-base problems, represented by their score on an 18-item paper and pencil test, the Acid-Base Concept Assessment (ABCA). The ABCA, consisting of both multiple-choice and short-answer items, was originally designed using a question-type by subtopic matrix, validated by a panel of experts, and refined through pilot studies and factor analysis to create the final instrument. The concept map task included a short introduction to concept mapping, a prototype concept map, a practice concept-mapping activity, and the instructions for the acid-base concept map task. The instruments were administered to chemistry students at two high schools; 108 subjects completed both instruments for this study. Factor analysis of ABCA results indicated that the test was unifactorial for these students, despite the intention to create an instrument with multiple "question-type" scales. Concept maps were scored both holistically and by counting valid concepts. The two approaches were highly correlated (r = 0.75). The correlation between ABCA score and concept-map score was 0.29 for holistically-scored concept maps and 0.33 for counted-concept maps. Although both correlations were significant, they accounted for only 8.8 and 10.2% of variance in ABCA scores, respectively. However, when the reliability of the instruments used is considered, more than 20% of the variance in ABCA scores may be explained by concept map scores. MANOVAs for ABCA and concept map scores by instructor, student gender, and year in school showed significant differences for both holistic and counted concept-map scores. Discriminant analysis revealed that the source of these differences was the instruction variable. Significant differences between classes receiving different instruction were found in the frequency of

  19. Quantum chemistry contribution to the understanding of the acid-base phenomena

    The various physical and chemical phenomena involved at the atomic and molecular level of a two material interface, are studied. When intimately in contact, intermolecular range forces are established between their atoms. These forces are divided in two categories: short range and long range forces, and according to the intervention rate, the bonding will be more or less strong. A quantitative approach, in terms of quantum chemistry of the so called acid-base interactions, is proposed and prospects for this approach with the view of enhancing or diminishing the bonding strength between two materials, are discussed

  20. Well-Posedness of MultiCriteria Network Equilibrium Problem

    Zhang, W.Y.

    2014-01-01

    New notions of ϵ-equilibrium flow and ${\\xi }_{{k}_{0}}$ -ϵ-equilibrium flow of multicriteria network equilibrium problem are introduced; an equivalent relation between vector ϵ-equilibrium pattern flow and ${\\xi }_{{k}_{0}}$ -ϵ-equilibrium flow is established. Then, the well-posedness of multicriteria network equilibrium problem is discussed.

  1. The acid-base and catalytic properties of the surface of ZnSe-CdSe solid solutions

    Acid-base properties of the surface of slid solutions ZnxCd1-xSe and initial binary semiconductor compounds (ZnSe, CdSe) were studied by the method of probe molecules on acid and base centers. Nature of the acid-base centers was ascertained, their strength and quantitative content on the system samples of different composition were evaluated. Acid-base properties were compared with catalytic ones in reference to propanol-2 decomposition. Similarity and difference in acid-base and catalytic properties of the surface of binary semiconductors and solid solutions were pointed out. Specific features of the solid solutions were detected, which are largely pronounced in the course of ascertaining the property-composition dependence

  2. Reflective Equilibrium: Epistemological or Political?

    Andrew Lister

    2016-01-01

    Full Text Available One of the reasons for ongoing interest in the work of political philosopher John Rawls is that he developed novel methods for thinking systematically about the nature of justice. This paper examines the moral and epistemological motivations for Rawls’s method of “reflective equilibrium,” and the tension between them in Kai Nielsen’s use of “wide reflective equilibrium” in the service of critical and emancipatory social theory. Une des raisons de l’intérêt soutenu pour l’oeuvre du philosophe politique John Rawls est qu’il a développé de nouvelles méthodes de réflexion systématique au sujet de la nature de la justice. Cet article étudie les motifs moraux et épistémologiques soutenant la méthode d’ «équilibre réflectif» de Rawls, et les tensions entre eux dans l’utilisation par Kai Nielsen d’ «équilibre réflectif étendu» au service de la théorie sociale critique et émancipatrice.

  3. Colin Rowe and ' Dynamic Equilibrium'

    Pablo López Marín

    2015-05-01

    Full Text Available AbstractIn 1944 Gyorgy Kepes published what undoubtless will be his most influential text, "The language of vision". What Kepes tried to do was a guide of grammar and syntax of vision, which allows to face art as purely sensory experience or just visual, devisted of any literary , semantic or sentimental meaning.Among all the concepts that Kepes developes in his essay perhaps the most decisive one is the so called dynamic equilibrium, which is introduced in this work for fi rst time, verbalizing something that was in the air, orbiting around the entire modern plastic but far only explained in an empirical way.Colin Rowe reverberates the recent readed kepesian ideas on his own writings Transparency: Literal and Phenomenal and Neo-'Classicism' and Modern Architecture I and II, when the author tries to highlight the founding principles of the modern movement refusing the plastic  dimension of the discipline . The article will try to expose and explain this influence.

  4. Ringed Accretion Disks: Equilibrium Configurations

    Pugliese, D.; Stuchlík, Z.

    2015-12-01

    We investigate a model of a ringed accretion disk, made up by several rings rotating around a supermassive Kerr black hole attractor. Each toroid of the ringed disk is governed by the general relativity hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluids. Properties of the tori can then be determined by an appropriately defined effective potential reflecting the background Kerr geometry and the centrifugal effects. The ringed disks could be created in various regimes during the evolution of matter configurations around supermassive black holes. Therefore, both corotating and counterrotating rings have to be considered as being a constituent of the ringed disk. We provide constraints on the model parameters for the existence and stability of various ringed configurations and discuss occurrence of accretion onto the Kerr black hole and possible launching of jets from the ringed disk. We demonstrate that various ringed disks can be characterized by a maximum number of rings. We present also a perturbation analysis based on evolution of the oscillating components of the ringed disk. The dynamics of the unstable phases of the ringed disk evolution seems to be promising in relation to high-energy phenomena demonstrated in active galactic nuclei.

  5. Convective Quasi-Equilibrium Reconsidered

    David J Raymond

    2011-08-01

    Full Text Available The hypothesis of convective quasi-equilibrium states that moist convection reacts almost instantly to drive the atmospheric temperature profile throughout the troposphere to one of a special subset of possible profiles. In a simple case this might consist of a moist adiabat with the saturated moist entropy of the adiabat equaling the moist entropy of the boundary layer. In more complex cases the target temperature profile might depend on the moisture profile as well as boundary layer conditions. We present evidence from analytical and numerical calculations which challenge the validity of this hypothesis. These calculations involve both a simple, physically based parameterization of the effects of convection on its environment and a complex cloud-resolving model. In both cases we show that imposed temperature perturbations in the lower troposphere are rapidly eliminated, while those in the upper troposphere are not. The rapid temperature relaxation in the lower troposphere is due to the near-instantaneous change in the precipitation rate and latent heat release provoked by the temperature anomaly. Water vapor is so limited in the upper troposphere that this process cannot act there.

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

    By using the potentiometric microtitration method, acidity constants, Ka, anionic, KAHA-, and cationic, KBHB+, homoconjugation constants, as well as molecular heteroconjugation, KBHA, 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 (KAHA- 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 lgKBHA reveal that the most stable heterocomplexes are formed by n-butylamine and acetic acid that are characterized by the smallest differences in pKa values

  7. Surface functionalization of two-dimensional metal chalcogenides by Lewis acid-base chemistry.

    Lei, Sidong; Wang, Xifan; Li, Bo; Kang, Jiahao; He, Yongmin; George, Antony; Ge, Liehui; Gong, Yongji; Dong, Pei; Jin, Zehua; Brunetto, Gustavo; Chen, Weibing; Lin, Zuan-Tao; Baines, Robert; Galvão, Douglas S; Lou, Jun; Barrera, Enrique; Banerjee, Kaustav; Vajtai, Robert; Ajayan, Pulickel

    2016-05-01

    Precise control of the electronic surface states of two-dimensional (2D) materials could improve their versatility and widen their applicability in electronics and sensing. To this end, chemical surface functionalization has been used to adjust the electronic properties of 2D materials. So far, however, chemical functionalization has relied on lattice defects and physisorption methods that inevitably modify the topological characteristics of the atomic layers. Here we make use of the lone pair electrons found in most of 2D metal chalcogenides and report a functionalization method via a Lewis acid-base reaction that does not alter the host structure. Atomic layers of n-type InSe react with Ti(4+) to form planar p-type [Ti(4+)n(InSe)] coordination complexes. Using this strategy, we fabricate planar p-n junctions on 2D InSe with improved rectification and photovoltaic properties, without requiring heterostructure growth procedures or device fabrication processes. We also show that this functionalization approach works with other Lewis acids (such as B(3+), Al(3+) and Sn(4+)) and can be applied to other 2D materials (for example MoS2, MoSe2). Finally, we show that it is possible to use Lewis acid-base chemistry as a bridge to connect molecules to 2D atomic layers and fabricate a proof-of-principle dye-sensitized photosensing device. PMID:26828848

  8. Site-specific acid-base properties of pholcodine and related compounds.

    Kovács, Z; Hosztafi, S; Noszál, B

    2006-11-01

    The acid-base properties of pholcodine, a cough-depressant agent, and related compounds including metabolites were studied by 1H NMR-pH titrations, and are characterised in terms of macroscopic and microscopic protonation constants. New N-methylated derivatives were also synthesized in order to quantitate site- and nucleus-specific protonation shifts and to unravel microscopic acid-base equilibria. The piperidine nitrogen was found to be 38 and 400 times more basic than its morpholine counterpart in pholcodine and norpholcodine, respectively. The protonation data show that the molecule of pholcodine bears an average of positive charge of 1.07 at physiological pH, preventing it from entering the central nervous system, a plausible reason for its lack of analgesic or addictive properties. The protonation constants of pholcodine and its derivatives are interpreted by comparing with related molecules of pharmaceutical interest. The pH-dependent relative concentrations of the variously protonated forms of pholcodine and morphine are depicted in distribution diagrams. PMID:17004059

  9. Manipulation of partially oriented hydroxyapatite building blocks to form flowerlike bundles without acid-base regulation.

    Wen, Zhenliang; Wang, Zihao; Chen, Jingdi; Zhong, Shengnan; Hu, Yimin; Wang, Jianhua; Zhang, Qiqing

    2016-06-01

    The application of hydroxyapatite (HAP) in different fields depends greatly on its morphology, composition and structure. Besides, the main inorganic building blocks of human bones and teeth are also HAP. Therefore, accurate shape and aggregation control and of hydroxyapatite particles will be of great interest. Herein, oriented bundles of flowerlike HAP nanorods were successfully prepared through hydrothermal treatment without acid-base regulation, with the mono-alkyl phosphate (MAP) and sodium citrate as surfactant and chelating agent, respectively. The prepared samples were characterized by the X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM) and zeta potential, the pH value and conductivity value of suspension were characterized by pH meter and conductivity measurement. The results showed that the MAP and citrate play an important role in assembly of HAP nanorods without acid-base regulation. Citrate calcium complex could decompose slowly and release citrate ions at hydrothermal conditions. Besides, the further decomposition of citrate ions could release aconitic acid as the reaction time prolongs. Moreover, the possible scheme for the formation process was discussed in detail. PMID:26930036

  10. The generalized Lewis acid-base titration of palladium and niobium

    The high thermodynamic stability of alloys composed of platinum group metals and group IVB and VB metals has been explained by an electronic interaction analogous to the Lewis acid-base concept for nontransition elements. The analogy is further demonstrated by the titration of palladium by addition of niobium. The activity of niobium in solid palladium was measured as a function of concentration by solid-state galvanic cells and study of the ternary oxide phase diagram. The galvanic cells were of the Pt/NbO2, Nb2O4.8/YDT/NbOy, Nb(Pd)/Pt where the solid electrolyte is yttria-doped thoria (YDT). Ternary phase diagrams for the Pd-Nb-O and Rh-Nb-O systems were obtained by characterizing samples equilibrated at 10000C. The phase relationships found in the ternary diagrams were also used to derive thermochemical data for the alloys. Thermochemical quantities for other acid-base stabilized alloys such as Nb-Rh, Ti-Pd, and Ti-Rh were also measured

  11. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review

    Hartati Hartati

    2013-06-01

    Full Text Available This paper reviews various types of heterogeneous acid-base catalysts for fragrances preparation. Catalytic activities of various types of heterogeneous acid and base catalysts in fragrances preparation, i.e. non-zeolitic, zeolitic, and mesoporous molecular sieves have been reported. Generally, heterogeneous acid catalysts are commonly used in fragrance synthesis as compared to heterogeneous base catalysts. Heteropoly acids and hydrotalcites type catalysts are widely used as heterogeneous acid and base catalysts, respectively. © 2013 BCREC UNDIP. All rights reservedReceived: 20th January 2013; Revised: 31st March 2013; Accepted: 1st April 2013[How to Cite: Hartati, H., Santoso, M., Triwahyono, S., Prasetyoko, D. (2013. Activities of Heterogeneous Acid-Base Catalysts for Fragrances Synthesis: A Review. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 14-33. (doi:10.9767/bcrec.8.1.4394.14-33][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4394.14-33] | View in  |

  12. A Prebiotic Chemistry Experiment on the Adsorption of Nucleic Acids Bases onto a Natural Zeolite

    Anizelli, Pedro R.; Baú, João Paulo T.; Gomes, Frederico P.; da Costa, Antonio Carlos S.; Carneiro, Cristine E. A.; Zaia, Cássia Thaïs B. V.; Zaia, Dimas A. M.

    2015-09-01

    There are currently few mechanisms that can explain how nucleic acid bases were synthesized, concentrated from dilute solutions, and/or protected against degradation by UV radiation or hydrolysis on the prebiotic Earth. A natural zeolite exhibited the potential to adsorb adenine, cytosine, thymine, and uracil over a range of pH, with greater adsorption of adenine and cytosine at acidic pH. Adsorption of all nucleic acid bases was decreased in artificial seawater compared to water, likely due to cation complexation. Furthermore, adsorption of adenine appeared to protect natural zeolite from thermal degradation. The C=O groups from thymine, cytosine and uracil appeared to assist the dissolution of the mineral while the NH2 group from adenine had no effect. As shown by FT-IR spectroscopy, adenine interacted with a natural zeolite through the NH2 group, and cytosine through the C=O group. A pseudo-second-order model best described the kinetics of adenine adsorption, which occurred faster in artificial seawaters.

  13. A study on the role of gelatin in methacrylic-acid-based gel dosimeters

    In radiotherapy treatment, polymer gel dosimetry can be used for verifying three-dimensional (3D) dose distributions. Gelatin is generally used as a gelling agent in the dosimeters. In this paper, another role of gelatin in a methacrylic-acid-based gel dosimeter (MAGAT) is investigated. Temperature increases due to exothermic polymerization in the irradiated gel are measured directly. Dose-R2 responses are also obtained using MRI. It is shown that no appreciable increases in either temperature or R2 are observed in MAGAT dosimeters made without gelatin, and that significant temperature and R2 increases are observed when very low gelatin concentrations are used. These results indicate that gelatin is an important enabler for radiation-induced free-radical polymerization in methacrylic-acid-based gels. When gelatin is replaced by amino acids, changes in temperature are observed, along with small changes in R2. The resulting dosimeter solutions remain transparent because the polymer does not precipitate as it does in regular MAGAT dosimeters containing gelatin. When the amino acids are replaced by acids without amino groups, no temperature or R2 changes are observed, indicating that no polymer forms. These results show that amino groups (and possibly other functional groups) on the gelatin catalyze the radiation-induced free-radical polymerization that occurs in MAGAT dosimeters.

  14. Fractionating vacuum thermal deposition of polyaniline films. Effect of post-deposition acid-base treatment

    Nekrasov, A.A. (Frumkin Institute of Electrochemistry, Russian Academy of Sciences, Leninskii Prospect 31, Moscow 117071 (Russian Federation)); Ivanov, V.F. (Frumkin Institute of Electrochemistry, Russian Academy of Sciences, Leninskii Prospect 31, Moscow 117071 (Russian Federation)); Gribkova, O.L. (Frumkin Institute of Electrochemistry, Russian Academy of Sciences, Leninskii Prospect 31, Moscow 117071 (Russian Federation)); Vannikov, A.V. (Frumkin Institute of Electrochemistry, Russian Academy of Sciences, Leninskii Prospect 31, Moscow 117071 (Russian Federation))

    1994-07-15

    Vacuum thermal evaporation of a single portion of chemically synthesized polyaniline (PAN) base powder was performed step-by-step within four temperature intervals in the 240-450 C range. The vapour was deposited on quartz and SnO[sub 2]-glass substrates, each fraction being deposited on a separate substrate. The samples obtained were subjected to cyclic contrast acid-base treatment, and UV-Vis spectra of the fractions after each treatment cycle were registered. The spectra of the as-deposited fractions appear to have little in common with conventional PAN spectra. The appearance of absorption bands essential for conventional PAN spectra is found to occur for some of the fractions only after the above treatment. This is apparently due to recombination of PAN oligomer radical fragments, formed in the course of the evaporation, resulting in restoration of PAN macromolecule structure. The recombination may be intensified by conformational changes during the acid-base treatment. Cyclic voltammetry curves for the most PAN-like fractions resemble the ones for conventional PAN. ((orig.))

  15. [The favorable effect of humic acid based complex micro-element preparations in cadmium exposure].

    Hudák, A; Náray, M; Nagy, I; Molnár, M; Gömöry, I; Ungváry, G

    1997-06-01

    The authors have studied the effect of consumption of a humic acid based complex microelement preparation (potassium, magnesium, iron, zinc, manganese, copper, vanadium, cobalt, molibden, selenium bound to humic acids) for six weeks (10 ml daily) on the biological exposure indices (blood and urine cadmium levels) and clinical laboratory parameters (liver and kidney tests, blood picture) of men (n = 18; 39.7 +/- 10.4 years of age;) working in cadmium exposure for 8.3 +/- 5.0 years. The initial mean blood and urine cadmium levels of the non-smoking subjects was twice higher than that of the non-smoking male controls living in the same urban area (n = 35), and significantly correlated with the length of exposure. Their mean serum alanin-aminotransferase, gamma-glutamyl-transferase, creatinine, uric acid and urinary N-acetyl-beta-D-glucosaminidase levels were significantly higher than that of the controls. After the six-week treatment blood cadmium level, activity of serum alanin-aminotransferase, serum uric acid and urinary protein concentrations decreased significantly, the abnormal serum iron levels normalized. According to this results, the absorption of cadmium decreased on the effect of the complex microelement supplementation and the adverse laboratory changes attributable partly to cadmium exposure improved. Therefore humic acid based complex microelement supplementation is recommended as an effective tool for prevention and health protection in occupational cadmium exposure as well as for smokers known to be considerably burdened by cadmium. PMID:9254361

  16. CHARGE DEVELOPMENT AND ACID-BASE CHARACTERISTICS OF SOIL AND COMPOST HUMIC ACIDS

    P. A. CAMPITELLI

    2003-09-01

    Full Text Available In previous works, the acid-base properties, charging behavior and chemical heterogeneity of humic substances have been studied using different mathematical equations to fit the experimental data. The objective of this research is to study the charge behavior, acid-base properties and analyze the chemical heterogeneity of humic acids (HA extracted from soil and composted municipal solid waste by potentiometric titrations. The humic acids extracted from compost have some characteristics and behavior similar to those obtained from soil. The negative charge development of HA extracted from composted material are lower than those extracted from soil and increase as ionic strength increase. The amount of carboxylic groups is lower in compost HA than in soil HA The heterogeneity of HA extracted from compost is higher than those extracted from soil. As the time of composting period increase the humification processes that take place trends to produce compost HA that has similar characteristics to soil HA. We suggest that HA extracted from composted material are macromolecules "like soil humic acids", i.e. "humiclike fraction"

  17. Acid-based hydrolysis processes for ethanol from lignocellulosic materials: A review

    Keikhosro Karimi

    2007-01-01

    Full Text Available Bioethanol is nowadays one of the main actors in the fuel market. It is currently produced from sugars and starchy materials, but lignocelluloses can be expected to be major feedstocks for ethanol production in the future. Two processes are being developed in parallel for conversion of lignocelluloses to ethanol, “acid-based” and “enzyme-based” processes. The current article is dedicated to review of progress in the “acid-based-hydrolysis” process. This process was used industrially in the 1940s, during wartime, but was not economically competitive afterward. However, intensive research and development on its technology during the last three decades, in addition to the expanding ethanol market, may revive the process in large scale once again. In this paper the ethanol market, the composition of lignocellulosic materials, concentrated- and dilute-acid pretreatment and hydrolysis, plug-flow, percolation, counter-current and shrinking-bed hydrolysis reactors, fermentation of hexoses and pentoses, effects of fermentation inhibitors, downstream processing, wastewater treatment, analytical methods used, and the current commercial status of the acid-based ethanol processes are reviewed.

  18. Novel sulfonated poly (ether ether keton)/polyetherimide acid-base blend membranes for vanadium redox flow battery applications

    Highlights: • SPEEK/PEI acid-base blend membranes are prepared for VRB applications. • The acid-base blend membranes have much lower vanadium ion permeability. • The energy efficiency of SPEEK/PEI maintain around 86.9% after 50 cycles. - Abstract: Novel acid-base blend membranes composed of sulfonated poly (ether ether ketone) (SPEEK) and polyetherimide (PEI) were prepared for vanadium redox flow battery (VRB). The blend membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electronic microscopy (SEM). The ion exchange capacity (IEC), proton conductivity, water uptake, vanadium ion permeability and mechanical properties were measured. As a result, the acid-base blend membranes exhibit higher water uptake, IEC and lower vanadium ion permeability compared to Nafion117 membranes and all these properties decrease with the increase of PEI. In VRB single cell test, the VRB with blend membranes shows lower charge capacity loss, higher coulombic efficiency (CE) and energy efficiency (EE) than Nafion117 membrane. Furthermore, the acid-base blend membranes present stable performance up to 50 cycles with no significant decline in CE and EE. All experimental results indicate that the SPEEK/PEI (S/P) acid-base blend membranes show promising prospects for VRB

  19. Vertical field and equilibrium calculation in ETE

    The free-boundary MHD equilibrium code HEQ is used to study the plasma behaviour in the tokamak ETE, with optimized compensations coils and vertical field coils. The changes on the equilibrium parameters for different plasma current values are also investigated. (author). 5 refs., 4 figs., 2 tabs

  20. Competitive equilibrium hyperinflation under rational expectations

    Sallum, Elvia Mureb; Barbosa, Fernando de Holanda; Cunha, Alexandre Barros da

    2005-01-01

    This paper shows that a competitive equilibrium model, where a representative agent maximizes welfare, expectations are rational and markets are in equilibrium can account for several hyperinflation stylized facts. The theory is built by combining two hypotheses, namely, a fiscal crisis that requires printing money to finance an increasing public deficit and a predicted change in an unsustainable fiscal regime.

  1. The method of reflective equilibrium and intuitions

    Langkau, Julia

    2013-01-01

    Reflective equilibrium has been considered a paradigm method involving intuitions. Some philosophers have recently claimed that it is trivial and can even accommodate the sort of scepticism about the reliability of intuitions advocated by experimental philosophers. I discuss several ways in which reflective equilibrium could be thought of as trivial and argue that it is inconsistent with scepticism about the reliability of intuitions.

  2. Equilibrium and stability of the multipole

    The equilibrium and linear ballooning mode stability of a plasma in an axisymmetric closed field line device such as the multipole is investigated. Two models of the plasma are used, a kinetic model and an ideal MHD model, and the results are compared. Numerical calculations are made of the equilibrium and of ballooning mode stability criteria in the Wisconsin Levitated Octupole device

  3. Zeroth Law, Entropy, Equilibrium, and All That

    Canagaratna, Sebastian G.

    2008-01-01

    The place of the zeroth law in the teaching of thermodynamics is examined in the context of the recent discussion by Gislason and Craig of some problems involving the establishment of thermal equilibrium. The concept of thermal equilibrium is introduced through the zeroth law. The relation between the zeroth law and the second law in the…

  4. Equilibrium figures in geodesy and geophysics.

    Moritz, H.

    There is an enormous literature on geodetic equilibrium figures, but the various works have not always been interrelated, also for linguistic reasons (English, French, German, Italian, Russian). The author attempts to systematize the various approaches and to use the standard second-order theory for a study of the deviation of the actual earth and of the equipotential reference ellipsoid from an equilibrium figure.

  5. Implementing an Equilibrium Law Teaching Sequence for Secondary School Students to Learn Chemical Equilibrium

    Ghirardi, Marco; Marchetti, Fabio; Pettinari, Claudio; Regis, Alberto; Roletto, Ezio

    2015-01-01

    A didactic sequence is proposed for the teaching of chemical equilibrium law. In this approach, we have avoided the kinetic derivation and the thermodynamic justification of the equilibrium constant. The equilibrium constant expression is established empirically by a trial-and-error approach. Additionally, students learn to use the criterion of…

  6. How Far from Equilibrium Is Active Matter?

    Fodor, Étienne; Nardini, Cesare; Cates, Michael E.; Tailleur, Julien; Visco, Paolo; van Wijland, Frédéric

    2016-07-01

    Active matter systems are driven out of thermal equilibrium by a lack of generalized Stokes-Einstein relation between injection and dissipation of energy at the microscopic scale. We consider such a system of interacting particles, propelled by persistent noises, and show that, at small but finite persistence time, their dynamics still satisfy a time-reversal symmetry. To do so, we compute perturbatively their steady-state measure and show that, for short persistent times, the entropy production rate vanishes. This endows such systems with an effective fluctuation-dissipation theorem akin to that of thermal equilibrium systems. Last, we show how interacting particle systems with viscous drags and correlated noises can be seen as in equilibrium with a viscoelastic bath but driven out of equilibrium by nonconservative forces, hence providing energetic insight into the departure of active systems from equilibrium.

  7. Equilibrium and Sudden Events in Chemical Evolution

    Weinberg, David H; Freudenburg, Jenna

    2016-01-01

    We present new analytic solutions for one-zone (fully mixed) chemical evolution models and explore their implications. In contrast to existing analytic models, we incorporate a realistic delay time distribution for Type Ia supernovae (SNIa) and can therefore track the separate evolution of $\\alpha$-elements produced by core collapse supernovae (CCSNe) and iron peak elements synthesized in both CCSNe and SNIa. In generic cases, $\\alpha$ and iron abundances evolve to an equilibrium at which element production is balanced by metal consumption and gas dilution, instead of continuing to increase over time. The equilibrium absolute abundances depend principally on supernova yields and the outflow mass loading parameter $\\eta$, while the equilibrium abundance ratio [$\\alpha$/Fe] depends mainly on yields and secondarily on star formation history. A stellar population can be metal-poor either because it has not yet evolved to equilibrium or because high outflow efficiency makes the equilibrium abundance itself low. Sy...

  8. Economic networks in and out of equilibrium

    Squartini, Tiziano

    2013-01-01

    Economic and financial networks play a crucial role in various important processes, including economic integration, globalization, and financial crises. Of particular interest is understanding whether the temporal evolution of a real economic network is in a (quasi-)stationary equilibrium, i.e. characterized by smooth structural changes rather than abrupt transitions. Smooth changes in quasi-equilibrium networks can be generally controlled for, and largely predicted, via an appropriate rescaling of structural quantities, while this is generally not possible for abrupt transitions in non-stationary networks. Here we study whether real economic networks are in or out of equilibrium by checking their consistency with quasi-equilibrium maximum-entropy ensembles of graphs. As illustrative examples, we consider the International Trade Network (ITN) and the Dutch Interbank Network (DIN). We show that, despite the globalization process, the ITN is an almost perfect example of quasi-equilibrium network, while the DIN ...

  9. Disturbances in equilibrium function after major earthquake

    Honma, Motoyasu; Endo, Nobutaka; Osada, Yoshihisa; Kim, Yoshiharu; Kuriyama, Kenichi

    2012-10-01

    Major earthquakes were followed by a large number of aftershocks and significant outbreaks of dizziness occurred over a large area. However it is unclear why major earthquake causes dizziness. We conducted an intergroup trial on equilibrium dysfunction and psychological states associated with equilibrium dysfunction in individuals exposed to repetitive aftershocks versus those who were rarely exposed. Greater equilibrium dysfunction was observed in the aftershock-exposed group under conditions without visual compensation. Equilibrium dysfunction in the aftershock-exposed group appears to have arisen from disturbance of the inner ear, as well as individual vulnerability to state anxiety enhanced by repetitive exposure to aftershocks. We indicate potential effects of autonomic stress on equilibrium function after major earthquake. Our findings may contribute to risk management of psychological and physical health after major earthquakes with aftershocks, and allow development of a new empirical approach to disaster care after such events.

  10. Hypoxia and Its Acid-Base Consequences: From Mountains to Malignancy.

    Swenson, Erik R

    2016-01-01

    Hypoxia, depending upon its magnitude and circumstances, evokes a spectrum of mild to severe acid-base changes ranging from alkalosis to acidosis, which can alter many responses to hypoxia at both non-genomic and genomic levels, in part via altered hypoxia-inducible factor (HIF) metabolism. Healthy people at high altitude and persons hyperventilating to non-hypoxic stimuli can become alkalotic and alkalemic with arterial pH acutely rising as high as 7.7. Hypoxia-mediated respiratory alkalosis reduces sympathetic tone, blunts hypoxic pulmonary vasoconstriction and hypoxic cerebral vasodilation, and increases hemoglobin oxygen affinity. These effects and others can be salutary or counterproductive to tissue oxygen delivery and utilization, based upon magnitude of each effect and summation. With severe hypoxia either in the setting of profound arterial hemoglobin desaturation and reduced O2 content or poor perfusion (ischemia) at the global or local level, metabolic and hypercapnic acidosis develop along with considerable lactate formation and pH falling to below 6.8. Although conventionally considered to be injurious and deleterious to cell function and survival, both acidoses may be cytoprotective by various anti-inflammatory, antioxidant, and anti-apoptotic mechanisms which limit total hypoxic or ischemic-reperfusion injury. Attempts to correct acidosis by giving bicarbonate or other alkaline agents under these circumstances ahead of or concurrent with reoxygenation efforts may be ill advised. Better understanding of this so-called "pH paradox" or permissive acidosis may offer therapeutic possibilities. Rapidly growing cancers often outstrip their vascular supply compromising both oxygen and nutrient delivery and metabolic waste disposal, thus limiting their growth and metastatic potential. However, their excessive glycolysis and lactate formation may not necessarily represent oxygen insufficiency, but rather the Warburg effect-an attempt to provide a large amount

  11. Acid-base balance and hydration status following consumption of mineral-based alkaline bottled water

    Heil Daniel P

    2010-09-01

    Full Text Available Abstract Background The present study sought to determine whether the consumption of a mineral-rich alkalizing (AK bottled water could improve both acid-base balance and hydration status in young healthy adults under free-living conditions. The AK water contains a naturally high mineral content along with Alka-PlexLiquid™, a dissolved supplement that increases the mineral content and gives the water an alkalizing pH of 10.0. Methods Thirty-eight subjects were matched by gender and self-reported physical activity (SRPA, hrs/week and then split into Control (12 women, 7 men; Mean +/- SD: 23 +/- 2 yrs; 7.2 +/- 3.6 hrs/week SRPA and Experimental (13 women, 6 men; 22 +/- 2 yrs; 6.4 +/- 4.0 hrs/week SRPA groups. The Control group consumed non-mineralized placebo bottled water over a 4-week period while the Experimental group consumed the placebo water during the 1st and 4th weeks and the AK water during the middle 2-week treatment period. Fingertip blood and 24-hour urine samples were collected three times each week for subsequent measures of blood and urine osmolality and pH, as well as total urine volume. Dependent variables were analyzed using multivariate repeated measures ANOVA with post-hoc focused on evaluating changes over time within Control and Experimental groups (alpha = 0.05. Results There were no significant changes in any of the dependent variables for the Control group. The Experimental group, however, showed significant increases in both the blood and urine pH (6.23 to 7.07 and 7.52 to 7.69, respectively, a decreased blood and increased urine osmolality, and a decreased urine output (2.51 to 2.05 L/day, all during the second week of the treatment period (P Conclusions Consumption of AK water was associated with improved acid-base balance (i.e., an alkalization of the blood and urine and hydration status when consumed under free-living conditions. In contrast, subjects who consumed the placebo bottled water showed no changes over the

  12. Lung compliance, plasma electrolyte levels and acid-base balance are affected by scorpion envenomation in anesthetized rats under mechanical ventilation.

    Andrade, Marcus V; Caramez, Maria Paula R; Abreu, Elnara Marcia N N; Dolnikoff, Marisa; Omar, Erick D; Velasco, Irineu T; Cunha-Melo, José R

    2004-05-01

    To determine the effects of Tityus serrulatus scorpion toxin on lung compliance and resistance, ionic equilibrium and acid-base balance over time in anesthetized and mechanically ventilated rats, we measured air flow, tracheal and esophageal pressure. Lung volume was obtained by electronic integration of airflow signal. Arterial blood samples were collected through a catheter at baseline (before) and 5, 15, 30 and 60 min after scorpion toxin injection for arterial blood gases, bicarbonate, and alkali reserve levels as well as for, sodium, potassium, magnesium, glucose, lactate, hematocrit, and osmolality analysis. Injection of the gamma fraction of the T. serrulatus scorpion venom in rats under mechanical ventilatory support leads to a continuous decrease in lung compliance secondary to pulmonary edema, but no change in airway resistance. The changes in arterial blood gases characterizing metabolic acidosis were accompanied by an increase in arterial lactate and glucose values, suggesting a scorpion toxin-induced lactic acidosis, in association with poor tissue perfusion (hypotension and low cardiac output). Moreover, scorpion toxin injection resulted in hyperosmolality, hyperkalemia, hypermagnesemia and an increase in hematocrit. The experiments have shown a clinically relevant animal model to study severe scorpion envenoming and may help to better understand the scorpion envenoming syndrome. PMID:15313452

  13. Development of the high-temperature, solid-state, electromotive force technique to study the thermodynamics of Lewis-acid-base transition metal alloys

    The basic principles of the Engel-Brewer theory of metals are summarized and illustrated. Definitions of words used to describe its fundamentals are clarified. The theory predicts the extreme stability of the Lewis-acid-base alloys. The thermodynamics of such alloys may be obtained through the use of oxide-electrolyte, electrochemical cells. Experimental techniques associated with the use of these cells are explained in detail. Much attention is given to the preparation and processing of the materials required. A selective review of the cell literature demonstrates frequent difficulty in obtaining accurate thermodynamic data. In an attempt to correct this situation, as well as to correct problems discovered in this work, the physical processes which create the cell emf are clearly identified. The fundamental understanding afforded by the resulting cell model implies the procedures used to both discover and eliminate errors. Those due to concentration overpotentials, reactive impurities in the gas phase, and interfacial reactions are carefully analyzed. The procedures used to test for and attain equilibrium in an alloy-oxide, powder compact are supported through identification of the transport processes that mediate equilibration

  14. Enabling the Tablet Product Development of 5-Fluorocytosine by Conjugate Acid Base Cocrystals.

    Perumalla, Sathyanarayana R; Paul, Shubhajit; Sun, Changquan C

    2016-06-01

    5-Fluorocytosine (FC) is a high-dose antifungal drug that challenges the development of a tablet product due to poor solid-state stability and tabletability. Using 2 pharmaceutically acceptable conjugate acid base (CAB) cocrystals of FC with HCl and acesulfame, we have developed commercially viable high loading FC tablets. The tablets were prepared by direct compression using nano-coated microcrystalline cellulose Avicel PH105 as a tablet binder, which provided both excellent tabletability and good flowability. Commercial manufacturability of formulations based on both CAB cocrystals was verified on a compaction simulator. The results from an expedited friability study were used to set the compaction force, which yielded tablets with sufficient mechanical strength and rapid tablet disintegration. This work demonstrates the potential value of CAB cocrystals in drug product development. PMID:27238493

  15. Unimolecular half-adders and half-subtractors based on acid-base reaction

    Wei JIANG; Hengyi ZHANG; Yu LIU

    2009-01-01

    According to the structural analysis of reported mole-cular processors with acids and bases as inputs, we proposed a general method for constructing molecular half-adders and/or half-subtractors based on acid-base reaction. The method is preliminarily supported by four molecular processors (8-hydroxyquinoline, 4-hydroxypyridine, 4-aminophenol and 5-amino-1-naphthol) capable of the elementary addition and/or subtraction algebraic operations. Noticeably, 8-hydroxyquinoline can mimic the functions of three logic devices, i.e. half-adder, half-subtractor and digital comparator, by the use of superposition and reconfi-guration. The method described in this paper may be useful not only for designing new unimolecular arithmetical processors with the same inputs and outputs as standard devices for the construction of future molecular computers, but it can also help us disclose the simplest molecules and biomolecules with computational properties concealed around us.

  16. Role of acid-base interactions in synthesis of cordierite from talc and sillimanite group minerals

    Avvakumov E.G.

    2013-01-01

    Full Text Available It has been found that the mechanical activation of mixtures of sillimanite group minerals with talc and silica additives in grinding-activating devices with periodic and flow action provides significant acceleration of their interaction with formation of cordierite at the subsequent high-temperature treatment. It is shown that the output of cordierite depends on nature of mineral: in mixture with a sillimanite it is considerably higher, than with an andalusite and kyanite, while the rate of mullitization of these minerals has opposite character. It means that the formation of mullite during heat treatment is not a limiting step in synthesis of cordierite. It is shown that the rate of reaction is determined by the difference in the acid-base properties of these minerals, which depend on the coordination of aluminum cations by oxygen ions, different for each of the modifications.

  17. Laser restoring the glass surface treated with acid-based paint

    Strusevich, Anastasia V.; Poltaev, Yuriy A.; Sinev, Dmitrii A.

    2013-11-01

    The modern city facilities are often being attacked by graffiti artists, and increasingly vandals leave "tags" using paints, which compound based on acids, hydrofluoric or acetic commonly. These paints not only ink the surface, but also increase the surface roughness, and such impact can not be corrected by conventional cleaning. Thus, it was requested to develop technology that would not only clean the surface, but also to restore its structure by smoothing out irregularities and roughness formed after exposure in acid. In this work we investigated the effect of restoring the surface of the glass, spoiled by acid-based paint and then treated with CO2-laser. During the experiments, it was found that it is real to create the single-step laser surface restoring technology.

  18. Some comments upon acid-base balance in teleost fishes and its relationship to environmental temperature

    Houston, A.H.

    1971-01-01

    It has been hypothesized that acid-base regulation in mammalian species is directed toward stabilization of body fluid pH, whereas among the poikilotherms control centers upon the maintenance of relative alkalinity. Consequently, given the known relationship between temperature and the dissociation constant of water reductions in mammalian body temperature should be accompanied by decreases in the OH/sup -//H/sup +/ ratio while, under similar circumstances, the pH of the poikilothermic tetrapods, extension of the concept of relative alkalinity regulation to teleost fishes is not wholly consistent with the data presently available. Recorded blood and plasma pH values for teleost fishes are generally below those reported for amphibians and reptiles, tending to fall within or below the levels observed in mammals under comparable thermal conditions. Moreover, they seemingly display little tendency to vary in an inverse fashion wth temperature.

  19. Identification and Optimization of Anthranilic Acid Based Inhibitors of Replication Protein A.

    Patrone, James D; Pelz, Nicholas F; Bates, Brittney S; Souza-Fagundes, Elaine M; Vangamudi, Bhavatarini; Camper, Demarco V; Kuznetsov, Alexey G; Browning, Carrie F; Feldkamp, Michael D; Frank, Andreas O; Gilston, Benjamin A; Olejniczak, Edward T; Rossanese, Olivia W; Waterson, Alex G; Chazin, Walter J; Fesik, Stephen W

    2016-04-19

    Replication protein A (RPA) is an essential single-stranded DNA (ssDNA)-binding protein that initiates the DNA damage response pathway through protein-protein interactions (PPIs) mediated by its 70N domain. The identification and use of chemical probes that can specifically disrupt these interactions is important for validating RPA as a cancer target. A high-throughput screen (HTS) to identify new chemical entities was conducted, and 90 hit compounds were identified. From these initial hits, an anthranilic acid based series was optimized by using a structure-guided iterative medicinal chemistry approach to yield a cell-penetrant compound that binds to RPA70N with an affinity of 812 nm. This compound, 2-(3- (N-(3,4-dichlorophenyl)sulfamoyl)-4-methylbenzamido)benzoic acid (20 c), is capable of inhibiting PPIs mediated by this domain. PMID:26748787

  20. Thermodynamics of several lewis-acid-base stabilized transition metal alloys

    Gibson, John K.; Brewer, Leo; Gingerich, Karl A.

    1984-11-01

    High-temperature (1425 to 2750 K) thermodynamic activities of one or both components of twenty-five binary alloys of a group IVB-VIB element (Ti, Zr, Hf, Nb, Ta, or W) with a platinum group element (Ru, Os, Ir, Pd, Pt, or Au) have been determined by equilibrating the alloy with the appropriate carbide and graphite, equilibrating with the nitride and nitrogen gas, or measuring the partial vapor pressure(s) thermogravimetrically or mass spectrometrically. The extraordinary stability of this class of transition metal alloy is attributed to a generalized Lewis-acid-base interaction involving valence d electrons, and the results of these investigations are interpreted within the context of this effect. Among the conclusions made are that a non-spherically-symmetrical crystal field significantly reduces the bonding effectiveness of certain valence d orbitals; the effect of the extent of derealization of these orbitals is also considered.

  1. Chemical composition and the acid-base properties of the InSb-ZnSe surface

    Acid-base properties and chemical composition of the surface of solid solutions and binary compounds of the system InSb-ZnSe powders and films 0.25-0.35 μm thick were studied using a complex of physicochemical methods. It was ascertained that the initial surface features largely acid properties with transition to low-basic ones in the series InSb → (InSb)x(ZnSe)1-x → ZnSe. There are two types of acid centers on the surface: the Lewis (electron-accepted) and Broensted ones (adsorbed water molecules and OH- groups). After thermal vacuum treatment the surface composition was similar to stoichiometric one

  2. Neural networks applied to determine the thermophysical properties of amino acid based ionic liquids.

    Cancilla, John C; Perez, Ana; Wierzchoś, Kacper; Torrecilla, José S

    2016-03-01

    A series of models based on artificial neural networks (ANNs) have been designed to estimate the thermophysical properties of different amino acid-based ionic liquids (AAILs). Three different databases of AAILs were modeled using these algorithms with the goal set to estimate the density, viscosity, refractive index, ionic conductivity, and thermal expansion coefficient, and requiring only data regarding temperature and electronic polarizability of the chemicals. Additionally, a global model was designed combining all of the databases to determine the robustness of the method. In general, the results were successful, reaching mean prediction errors below 1% in many cases, as well as a statistically reliable and accurate global model. Attaining these successful models is a relevant fact as AAILs are novel biodegradable and biocompatible compounds which may soon make their way into the health sector forming a part of useful biomedical applications. Therefore, understanding the behavior and being able to estimate their thermophysical properties becomes crucial. PMID:26899458

  3. Study on acid- base disturbance in patients with posttraumatic multiple organ dysfunction syndrome

    2000-01-01

    Objective: To investigate the classification and incidence of acid-base disturbance (ABD) in the patients with post-traumatic multiple organ dysfunction syndrome (MODS). Methods: A total of 119 patients with MODS were examined with arterial blood gas analysis and serum electrolytes detection for 675 times in this study. Results: Different types of ABD existed in 647 times out of 675 times (95.9%) of blood-gas analyses. There were 270 times (41.7%) of simple ABD, 271 times (41.9%) of double ABD and 106 times (16.4%) of triple ABD. Among which, 404 times (62.4%) were in respiratory alkalosis (RAL), 332 times (51.3%) in metabolic acidosis (MA), 227 times (35.1% ) in metabolic alkalosis (MAL) and 167 times (25.8%) in respiratory acidosis (RA). In this study, 79 cases (66.4%) out of 119cases with MODS died from these kinds of ABD. Conclusions: It suggests that in the early stage of MODS, RAL with or without hypoxemia may exist, and later on, MA or even triple ABD may occur. In order to detect and correct the primary disorders as early as possible, it is important to keep the balance of hydrolyte. The treatment of primary diseases is also important.Disorders of acid-base balance were corrected according to pH standard values, anion gap (AG) and the potential [HCO3- ] were also calculated simultaneously. When pH was more than 7.50 or lower than 7.20, it is necessary to give drugs of acidity or alkalinity to the patients with ABD to maintain pH value within a normal range.

  4. Acid-base balance in the developing marsupial: from ectotherm to endotherm.

    Andrewartha, Sarah J; Cummings, Kevin J; Frappell, Peter B

    2014-05-01

    Marsupial joeys are born ectothermic and develop endothermy within their mother's thermally stable pouch. We hypothesized that Tammar wallaby joeys would switch from α-stat to pH-stat regulation during the transition from ectothermy to endothermy. To address this, we compared ventilation (Ve), metabolic rate (Vo2), and variables relevant to blood gas and acid-base regulation and oxygen transport including the ventilatory requirements (Ve/Vo2 and Ve/Vco2), partial pressures of oxygen (PaO2), carbon dioxide (PaCO2), pHa, and oxygen content (CaO2) during progressive hypothermia in ecto- and endothermic Tammar wallabies. We also measured the same variables in the well-studied endotherm, the Sprague-Dawley rat. Hypothermia was induced in unrestrained, unanesthetized joeys and rats by progressively dropping the ambient temperature (Ta). Rats were additionally exposed to helox (80% helium, 20% oxygen) to facilitate heat loss. Respiratory, metabolic, and blood-gas variables were measured over a large body temperature (Tb) range (∼15-16°C in both species). Ectothermic joeys displayed limited thermogenic ability during cooling: after an initial plateau, Vo2 decreased with the progressive drop in Tb. The Tb of endothermic joeys and rats fell despite Vo2 nearly doubling with the initiation of cold stress. In all three groups the changes in Vo2 were met by changes in Ve, resulting in constant Ve/Vo2 and Ve/Vco2, blood gases, and pHa. Thus, although thermogenic capability was nearly absent in ectothermic joeys, blood acid-base regulation was similar to endothermic joeys and rats. This suggests that unlike some reptiles, unanesthetized mammals protect arterial blood pH with changing Tb, irrespective of their thermogenic ability and/or stage of development. PMID:24627357

  5. A Multi Period Equilibrium Pricing Model

    Pirvu, Traian A

    2012-01-01

    In this paper, we propose an equilibrium pricing model in a dynamic multi-period stochastic framework with uncertain income streams. In an incomplete market, there exist two traded risky assets (e.g. stock/commodity and weather derivative) and a non-traded underlying (e.g. temperature). The risk preferences are of exponential (CARA) type with a stochastic coefficient of risk aversion. Both time consistent and time inconsistent trading strategies are considered. We obtain the equilibriums prices of a contingent claim written on the risky asset and non-traded underlying. By running numerical experiments we examine how the equilibriums prices vary in response to changes in model parameters.

  6. Rotamak equilibrium calculations using the PEST code

    This report describes the use of the equilibrium part of the Princeton equilibrium and stability code PEST to model rotamak equilibria with an applied toroidal magnetic field. An overview of the code is provided, together with a list of required input data. The simulation of a range of equilibria measured in the ANSTO rotamak shows that the rotamak approximately satisfies magnetohydrodynamic equilibrium. Of particular interest is the presence of large diamagnetic poloidal current about the magnetic axis which produces a peak in the plasma pressure on the magnetic axis. For a low toroidal field, however, poloidal current of opposite direction is simultaneously driven on flux surfaces distant from the magnetic axis, producing paramagnetism

  7. Equilibrium solubilities of iodine vapor in water

    Equilibrium solubilities of iodine vapor in water were measured by introducing iodine vapor, in equilibrium with solid iodine, into water and by circulating it in a closed system, and Henry's law constants were determined. Equilibrium distributions of iodine vapor between a gas phase and an aqueous phase were also measured by another method, and partition coefficients were determined. The solubilities of iodine vapor in water estimated from both the Henry's law constants and the partition coefficients are compared with those of solid iodine reported in the literature. Thermodynamic parameters for the hydration of iodine vapor are evaluated experimentally. (author)

  8. Differential adsorption of nucleic acid bases: Relevance to the origin of life

    Sowerby, Stephen J.; Cohn, Corey A; Heckl, Wolfgang M.; Holm, Nils G

    2001-01-01

    The adsorption of organic molecules onto the surfaces of inorganic solids has long been considered a process relevant to the origin of life. We have determined the equilibrium adsorption isotherms for the nucleic acid purine and pyrimidine bases dissolved in water on the surface of crystalline graphite. The markedly different adsorption behavior of the bases describes an elutropic series: guanine > adenine > hypoxanthine > thymine > cytosine > uracil. We propose th...

  9. Quasilocal energy and thermodynamic equilibrium conditions

    Uzun, Nezihe

    2015-01-01

    Equilibrium thermodynamic laws are typically applied to horizons in general relativity without stating the conditions that bring them into equilibrium. We fill this gap by applying a new thermodynamic interpretation to a generalized Raychaudhuri equation for a closed spacelike 2-surface, the "screen", which encompasses a system of arbitrary size in nonequilibrium with its surroundings in general. In the case of spherical symmetry this enables us to identify quasilocal thermodynamic potentials directly related to standard quasilocal energy definitions. Quasilocal thermodynamic equilibrium is defined by minimizing the mean extrinsic curvature of the screen. Moreover, without any direct reference to surface gravity, we find that the system comes into quasilocal thermodynamic equilibrium when the screen is located at a generalized apparent horizon. Examples of the Schwarzschild, Friedmann-Lemaitre and Lemaitre-Tolman geometries are investigated and compared. Conditions for the quasilocal thermodynamic and hydrody...

  10. Plasma equilibrium and instabilities in tokamaks

    A phenomenological introduction of some of the main theoretical and experimental features on equilibrium and instabilities in tokamaks is presented. In general only macroscopic effects are considered, being the plasma described as a fluid. (L.C.)

  11. Stochastic approach to equilibrium and nonequilibrium thermodynamics.

    Tomé, Tânia; de Oliveira, Mário J

    2015-04-01

    We develop the stochastic approach to thermodynamics based on stochastic dynamics, which can be discrete (master equation) and continuous (Fokker-Planck equation), and on two assumptions concerning entropy. The first is the definition of entropy itself and the second the definition of entropy production rate, which is non-negative and vanishes in thermodynamic equilibrium. Based on these assumptions, we study interacting systems with many degrees of freedom in equilibrium or out of thermodynamic equilibrium and how the macroscopic laws are derived from the stochastic dynamics. These studies include the quasiequilibrium processes; the convexity of the equilibrium surface; the monotonic time behavior of thermodynamic potentials, including entropy; the bilinear form of the entropy production rate; the Onsager coefficients and reciprocal relations; and the nonequilibrium steady states of chemical reactions. PMID:25974471

  12. Equilibrium Reconstruction on the Large Helical Device

    Samuel A. Lazerson, D. Gates, D. Monticello, H. Neilson, N. Pomphrey, A. Reiman S. Sakakibara, and Y. Suzuki

    2012-07-27

    Equilibrium reconstruction is commonly applied to axisymmetric toroidal devices. Recent advances in computational power and equilibrium codes have allowed for reconstructions of three-dimensional fields in stellarators and heliotrons. We present the first reconstructions of finite beta discharges in the Large Helical Device (LHD). The plasma boundary and magnetic axis are constrained by the pressure profile from Thomson scattering. This results in a calculation of plasma beta without a-priori assumptions of the equipartition of energy between species. Saddle loop arrays place additional constraints on the equilibrium. These reconstruction utilize STELLOPT, which calls VMEC. The VMEC equilibrium code assumes good nested flux surfaces. Reconstructed magnetic fields are fed into the PIES code which relaxes this constraint allowing for the examination of the effect of islands and stochastic regions on the magnetic measurements.

  13. Effect of Ultrasound on Desorption Equilibrium

    秦炜; 原永辉; 戴猷元

    2001-01-01

    Effects of ultrasound on intensification of separation process were investigated through the experiment of desorption equilibrium behavior. Tri-butyl phosphate (TBP) on NKA-X resin and phenol on a solvent impregnated resin, CL-TBP resin, were used for desorption processes. The desorption rate was measured with and without ultrasound. Desorption equilibrium was studied under various ultrasonic power densities or thermal infusion. Results showed that the desorption rate with ultrasound was much higher than that with normal thermal infusion. Both ultrasound and thermal infusion broke the desorption equilibrium existed at room temperature. However, after the systems were cooled down, the amount of solute desorbed in the liquid phase in the presence of ultrasound was much higher than that at the temperature corresponding to the same ultrasound power. It is proved that the initial desorption equilibrium was broken as a result of the spot energy effect of ultrasound.

  14. On financial equilibrium with intermediation costs

    Markeprand, Tobias Ejnar

    2008-01-01

    This paper studies the set of competitive equilibria in financial economies with intermediation costs. We consider an arbitrary dividend structure, which includes options and equity with limited liabilities.We show a general existence result and upper-hemi continuity of the equilibrium...... correspondence. Finally, we prove that when intermediation costs approach zero, unbounded volume of asset trades is a necessary and sufficient condition, provided that, there is no financial equilibrium without intermediation costs....

  15. Default and Credit Constraint in General equilibrium

    Xavier Ragot; François Le Grand

    2011-01-01

    We study an economy where infinitely living agents face uninsurable shocks and are allowed default on their debt. After having defaulted, agents are excluded from the economy. We present a equilibrium definition allowing for both credit constraints and default inequilibrium. Indeed, existing theories introduce either default of credit constraint in general equilibrium, but never both. We prove that the optimal allocation includes both credit constraints and default, while the market allocatio...

  16. Existence and stability of Nash equilibrium

    Carmona, Guilherme

    2012-01-01

    The book aims at describing the recent developments in the existence and stability of Nash equilibrium. The two topics are central to game theory and economics and have been extensively researched. Recent results on existence and stability of Nash equilibrium are scattered and the relationship between them has not been explained clearly. The book will make these results easily accessible and understandable to researchers in the field.

  17. Equilibrium labour turnover, firm growth and unemployment

    Coles, Melvyn G; Dale T. Mortensen

    2012-01-01

    This paper identifies a data-consistent, equilibrium model of unemployment, wage dispersion, quit turnover and firm growth dynamics. In a separating equilibrium, more productive firms signal their type by paying strictly higher wages in every state of the market. Workers optimally quit to firms paying a higher wage and so move effciently from less to more productive firms. Start-up firms are initially small and grow endogenously over time. Consistent with Gibrat's law, individual firm growth ...

  18. The Cournot Equilibrium for n Firms

    Gina Ioan

    2015-05-01

    Full Text Available Oligopoly is a market situation where there are a small number of bidders (at least two of a good non-substituent and a sufficient number of consumers. The paper analyses the Cournot equilibrium in both cases where each firm assumes the role of leadership and after when firms act simultaneously on market. There are obtained the equilibrium productions, maximum profits and sales price.

  19. An Equilibrium Analysis of Real Estate Leases

    Steven R. Grenadier

    2005-01-01

    This article provides a unified equilibrium approach to valuing commercial real estate leases. Using a game-theoretic variant of real options analysis, the underlying real estate asset market is modeled as a continuous-time Nash equilibrium, where developers make construction decisions under demand uncertainty. Then, using the economic notion that leasing represents the purchase of the use of the asset over a specified time, I use a contingent-claims approach to value many of the most common ...

  20. Equilibrium fluctuation energy of gyrokinetic plasma

    The thermal equilibrium electric field fluctuation energy of the gyrokinetic model of magnetized plasma is computed, and found to be smaller than the well-known result (k)/8π = 1/2T/[1 + (klambda/sub D/)2] valid for arbitrarily magnetized plasmas. It is shown that, in a certain sense, the equilibrium electric field energy is minimum in the gyrokinetic regime. 13 refs., 2 figs

  1. original: Operational spatial computable general equilibrium modeling

    Johannes BrÃcker

    1998-01-01

    A prototype spatial computable general equilibrium model is developed and illustrated by a numerical example. The theoretical basis is a complete Arrow-Debreu equilibrium under perfect competition. The leading principle of model design is parsimony: The specification restricts the number of parameters in a way allowing for a model calibration relying on a limited data base, which is readily available in a country with a well developed statistical service. No "data generating" first stage, usi...

  2. Thermal Denaturation of Proteins and Chemical Equilibrium

    Moroni, Laura; Gellini, Cristina; Remigio Salvi, Pier

    2015-01-01

    The thermal denaturation of proteins is considered as a process by means of which chemical equilibrium can be introduced to undergraduate students of Chemistry related curricula. In this approach chemical potential μ, Gibbs energy G, degree of advancement ξ and Le Châtelier principle are integrated with chemical equilibrium. With reference to α-Chymotrypsinogen A as a test case, the process is discussed in terms of a simplified two-state model. The activity is addressed to physical chemistry ...

  3. The Theory of Variances in Equilibrium Reconstruction

    Zakharov, Leonid E.; Lewandowski, Jerome; Foley, Elizabeth L.; Levinton, Fred M.; Yuh, Howard Y.; Drozdov, Vladimir; McDonald, Darren

    2008-01-14

    The theory of variances of equilibrium reconstruction is presented. It complements existing practices with information regarding what kind of plasma profiles can be reconstructed, how accurately, and what remains beyond the abilities of diagnostic systems. The σ-curves, introduced by the present theory, give a quantitative assessment of quality of effectiveness of diagnostic systems in constraining equilibrium reconstructions. The theory also suggests a method for aligning the accuracy of measurements of different physical nature.

  4. The Theory of Variances in Equilibrium Reconstruction

    The theory of variances of equilibrium reconstruction is presented. It complements existing practices with information regarding what kind of plasma profiles can be reconstructed, how accurately, and what remains beyond the abilities of diagnostic systems. The σ-curves, introduced by the present theory, give a quantitative assessment of quality of effectiveness of diagnostic systems in constraining equilibrium reconstructions. The theory also suggests a method for aligning the accuracy of measurements of different physical nature

  5. Theory for non-equilibrium statistical mechanics.

    Attard, Phil

    2006-08-21

    This paper reviews a new theory for non-equilibrium statistical mechanics. This gives the non-equilibrium analogue of the Boltzmann probability distribution, and the generalization of entropy to dynamic states. It is shown that this so-called second entropy is maximized in the steady state, in contrast to the rate of production of the conventional entropy, which is not an extremum. The relationships of the new theory to Onsager's regression hypothesis, Prigogine's minimal entropy production theorem, the Langevin equation, the formula of Green and Kubo, the Kawasaki distribution, and the non-equilibrium fluctuation and work theorems, are discussed. The theory is worked through in full detail for the case of steady heat flow down an imposed temperature gradient. A Monte Carlo algorithm based upon the steady state probability density is summarized, and results for the thermal conductivity of a Lennard-Jones fluid are shown to be in agreement with known values. Also discussed is the generalization to non-equilibrium mechanical work, and to non-equilibrium quantum statistical mechanics. As examples of the new theory two general applications are briefly explored: a non-equilibrium version of the second law of thermodynamics, and the origin and evolution of life. PMID:16883388

  6. Controlled synthesis of multi-morphology Te crystals by a convenient Lewis acid/base-assisted solvothermal method

    This paper reports on the controlled growth of multi-morphology Te crystals by a convenient Lewis acid/base-assisted solvothermal method for the first time. The morphological transformation from one-dimension (1D) nanostructures to 2D hierarchical flowerlike microarchitecture has been observed. The nanorods and nanowires with a well-defined crystallographical structure and the hierarchical flowers microarchitecture were obtained by changing the Lewis acids/bases. Lewis acids/bases were found to be crucial for the formation of the products by not only acting as the pH regulator but also as the shape controller, owing to their hydrolysis in the solvent to in situ form H+/OH− and hydrates. The results suggest that this should be an effective approach to the control the growth of t-Te crystals with interesting multiple morphologies, which are of interest for both theoretical investigations and practical applications.

  7. Analysis of the low-pressure plasma pretreated polymer surface in terms of acid-base approach

    Kraus, Eduard; Orf, Lukas; Baudrit, Benjamin; Heidemeyer, Peter; Bastian, Martin; Bonenberger, Ramona; Starostina, Irina; Stoyanov, Oleg

    2016-05-01

    We demonstrate the use of a modern wetting method for determining the acid-base properties of treated polymer surfaces for different plastics and adhesives. The effect of the surface treatment with low pressure plasma was evaluated from the viewpoint of acid-base approach with plastics polyoxymethylene (POM) and polyetheretherketone (PEEK). The correlations between the acid-base properties and the identified mechanical tensile strengths of adhesive bonded joints were evaluated and discussed. In the investigated range the determination coefficients for POM and PEEK were calculated to R2 = 0.93 and R2 = 0.97, respectively. These relatively high determination coefficients showed a good correlation between the mechanical strength and the acidity parameter ΔDshort for use in bonding technology for surface pretreatment of polymers with LPP.

  8. Continuous Renal Replacement Therapy for the Management of Acid-Base and Electrolyte Imbalances in Acute Kidney Injury.

    Yessayan, Lenar; Yee, Jerry; Frinak, Stan; Szamosfalvi, Balazs

    2016-05-01

    Continuous renal replacement therapy (CRRT) is used to manage electrolyte and acid-base imbalances in critically ill patients with acute kidney injury. Although a standard solution and prescription is acceptable in most clinical circumstances, specific disorders may require a tailored approach such as adjusting fluid composition, regulating CRRT dose, and using separate intravenous infusions to mitigate and correct these disturbances. Errors in fluid prescription, compounding, or delivery can be rapidly fatal. This article provides an overview of the principles of acid-base and electrolyte management using CRRT. PMID:27113697

  9. Acid-base behavior in hydrothermal processing of wastes. 1998 annual progress report

    'A new technology, hydrothermal oxidation (also called supercritical water oxidation), is being developed to treat high level nuclear wastes. Nitrates are reduced to nitrogen; furthermore, phosphates, alumina sludge, and chromium are solubilized, and the sludge is reconstituted as fine oxide particles. A major obstacle to development of this technology has been a lack of scientific knowledge of chemistry in hydrothermal solution above 350 C, particularly acid-base behavior, and transport phenomena, which is needed to understand corrosion, metal-ion complexation, and salt precipitation and recovery. The objective is to provide this knowledge with in-situ UV-vis spectroscopic measurements and fully molecular computer simulation. A major objective of the experimental studies has been to determine the equilibria for Cr(VI) up to 420 C as this is a key species to be removed from nuclear wastes. A wide range of concentrations of KOH and perchloric acid were utilized to manipulate the acid-base equilibria and to understand the effects of ion solvation and ion pairing. The second system is the equilibria between nitric acid, nitrous acid, nitrogen dioxide, nitrite and nitrate ions and oxygen. For both of these systems, chemical equilibria has not been measured previously in hydrothermal solution at these temperatures. On the theoretical side, the authors have focused on the study of the transport properties of aqueous ions in supercritical water. The motivation for these studies is two fold. First, although transport coefficients are fundamental to solution chemistry reaction rates, the behavior of such transport properties over wide ranges of density and temperature are not well established experimentally, particularly at the densities typically of interest (< 0.5 g/cc). Second, due to practical challenges, ionic association equilibria in SCW is typically accessed via measurements of conductivity followed by analysis through a theoretical model that incorporates ion

  10. Correlating multidimensional fetal heart rate variability analysis with acid-base balance at birth

    Fetal monitoring during labour currently fails to accurately detect acidemia. We developed a method to assess the multidimensional properties of fetal heart rate variability (fHRV) from trans-abdominal fetal electrocardiogram (fECG) during labour. We aimed to assess this novel bioinformatics approach for correlation between fHRV and neonatal pH or base excess (BE) at birth. We enrolled a prospective pilot cohort of uncomplicated singleton pregnancies at 38–42 weeks’ gestation in Milan, Italy, and Liverpool, UK. Fetal monitoring was performed by standard cardiotocography. Simultaneously, with fECG (high sampling frequency) was recorded. To ensure clinician blinding, fECG information was not displayed. Data from the last 60 min preceding onset of second-stage labour were analyzed using clinically validated continuous individualized multiorgan variability analysis (CIMVA) software in 5 min overlapping windows. CIMVA allows simultaneous calculation of 101 fHRV measures across five fHRV signal analysis domains. We validated our mathematical prediction model internally with 80:20 cross-validation split, comparing results to cord pH and BE at birth. The cohort consisted of 60 women with neonatal pH values at birth ranging from 7.44 to 6.99 and BE from −0.3 to −18.7 mmol L−1. Our model predicted pH from 30 fHRV measures (R2 = 0.90, P < 0.001) and BE from 21 fHRV measures (R2 = 0.77, P < 0.001). Novel bioinformatics approach (CIMVA) applied to fHRV derived from trans-abdominal fECG during labor correlated well with acid-base balance at birth. Further refinement and validation in larger cohorts are needed. These new measurements of fHRV might offer a new opportunity to predict fetal acid-base balance at birth. (fast track communication)

  11. α-Gel formation by amino acid-based gemini surfactants.

    Sakai, Kenichi; Ohno, Kiyomi; Nomura, Kazuyuki; Endo, Takeshi; Sakamoto, Kazutami; Sakai, Hideki; Abe, Masahiko

    2014-07-01

    Ternary mixtures being composed of surfactant, long-chain alcohol, and water sometimes form a highly viscous lamellar gel with a hexagonal packing arrangement of their crystalline hydrocarbon chains. This molecular assembly is called "α-crystalline phase" or "α-gel". In this study, we have characterized α-gels formed by the ternary mixtures of amino acid-based gemini surfactants, 1-hexadecanol (C16OH), and water. The surfactants used in this study were synthesized by reacting dodecanoylglutamic acid anhydride with alkyl diamines and abbreviated as 12-GsG-12 (s: the spacer chain length of 2, 5, and 8 methylene units). An amino acid-based monomeric surfactant, dodecanoylglutamic acid (12-Glu), was also used for comparison. At a fixed water concentration the melting point of the α-gel increased with increasing C16OH concentration, and then attained a saturation level at the critical mole ratio of 12-GsG-12/C16OH = 1/2 under the normalization by the number of hydrocarbon chains of the surfactants. This indicates that, to obtain the saturated α-gel, a lesser amount of C16OH is required for the gemini surfactants than for the monomeric one (the critical mole ratio of 12-Glu/C16OH = 1/3). Small- and wide-angle X-ray scattering measurements demonstrated an increase in the long-range d-spacing of the saturated α-gels in the order 12-Glu gemini surfactant systems, the decreased spacer chain length resulted in the increased maximum viscosity and elastic modulus of the saturated α-gels at a given water concentration. This is caused by the decreased amount of excess water being present outside the α-gel structure (or the increased amount of water incorporated between the surfactant-alcohol bilayers). To the best of our knowledge, this is the first report focusing on the formation of α-gel in gemini surfactant systems. PMID:24912111

  12. Comparative bioavailability studies of citric acid and malonic acid based aspirin effervescent tablets

    Anju Gauniya

    2010-01-01

    Full Text Available Purpose: The present investigation is aimed at comparing the pharmacokinetic profile (Bioavailability of aspirin in tablet formulations, which were prepared by using different effervescent excipients such as citric acid and malonic acid. Materials and Methods: The relative bioavailability and pharmacokinetics of citric acid based aspirin effervescent tablet (Product A and malonic acid based aspirin effervescent tablet (Product B formulations were evaluated for an in-vitro dissolution study and in-vivo bioavailability study, in 10 normal healthy rabbits. The study utilized a randomized, crossover design with a one-week washout period between doses. Blood samples were collected at 0, 1, 2, 4, 6, 8, 12 and 24 hours following a 100 mg/kg dose. Plasma samples were assayed by High Performance Liquid Chromatography. T max , C max , AUC 0-24 , AUC 0- ∞, MRT, K a, and relative bioavailability were estimated using the traditional pharmacokinetic methods and were compared by using the paired t-test. Result: In the present study, Products A and B showed their T max , C max , AUC 0-24 , AUC 0- ∞, MRT, and K a values as 2.5 h, 2589 ± 54.79 ng/ml, 9623 ± 112.87 ng.h/ml, 9586 ± 126.22 ng.h/ml, 3.6 ± 0.10 h, and 0.3698 ± 0.003 h -1 for Product A and 3.0 h, 2054 ± 55.79 ng/ml, 9637 ± 132.87 ng.h/ml, 9870 ± 129.22 ng.h/ml, 4.76 ± 0.10 h, and 0.3812 ± 0.002 h -1 for Product B, respectively. Conclusion: The results of the paired t-test of pharmacokinetics data showed that there was no significant difference between Products A and B. From both the in vitro dissolution studies and in vivo bioavailability studies it was concluded that products A and B had similar bioavailability.

  13. Historical perspective on the role of the kidney in acid-base regulation.

    Smogorzewski, Miroslaw J

    2009-01-01

    Early observations on the acidity of normal urine by J. B. von Helmont (1527-1644) and on urine content of sulfate, phosphate and carbonate by J. J. Berzelius (1779-1848), followed by the studies of Bence Jones (1813-1878) on the connection between food, nutrition and urine acidity, pointed to the role of the kidney in regulation of acid-base status in humans and animals. The next important steps in this field of science were studies by F. Walter (1877) on decreased "alkali" in blood and increased ammonia in the urine of dogs after infusion into their blood of hydrochloric acid, and the observations of B. Naunyn (1939-1925) and O. Minkowski (1853-1931) on the presence of beta-hydroxybutyric acid in urine and on increased ammonia excretion in urine from patients with diabetic coma. Also it was found that patients with uremia had decreased titratable "alkali' in blood (R. von Jaksch 1855-1947) and reduced ability to excrete ammonia (W. W. Palmer and L. J. Henderson 1915). Finally, studies by R. F. Pitts (1908-1977) defined the role of the kidney in reabsorption of bicarbonate in the tubules and linked hydrogen secretion to sodium excretion in the urine. PMID:20013742

  14. A facile nanoaggregation strategy for oral delivery of hydrophobic drugs by utilizing acid base neutralization reactions

    Chen, Huabing; Wan, Jiangling; Wang, Yirui; Mou, Dongsheng; Liu, Hongbin; Xu, Huibi; Yang, Xiangliang

    2008-09-01

    Nanonization strategies have been used to enhance the oral availability of numerous drugs that are poorly soluble in water. Exploring a facile nanonization strategy with highly practical potential is an attractive focus. Here, we report a novel facile nanoaggregation strategy for constructing drug nanoparticles of poorly soluble drugs with pH-dependent solubility by utilizing acid-base neutralization in aqueous solution, thus facilitating the exploration of nanonization in oral delivery for general applicability. We demonstrate that hydrophobic itraconazole dissolved in acid solution formed a growing core and aggregated into nanoparticles in the presence of stabilizers. The nanoparticles, with an average diameter of 279.3 nm and polydispersity index of 0.116, showed a higher dissolution rate when compared with the marketed formulation; the average dissolution was about 91.3%. The in vivo pharmacokinetic studies revealed that the nanoparticles had a rapid absorption and enhanced oral availability. The diet state also showed insignificant impact on the absorption of itraconazole from nanoparticles. This nanoaggregation strategy is a promising nanonization method with a facile process and avoidance of toxic organic solvents for oral delivery of poorly soluble drugs with pH-dependent solubility and reveals a highly practical potential in the pharmaceutical and chemical industries.

  15. Stearic acid based oleogels: a study on the molecular, thermal and mechanical properties.

    Sagiri, S S; Singh, Vinay K; Pal, K; Banerjee, I; Basak, Piyali

    2015-03-01

    Stearic acid and its derivatives have been used as gelators in food and pharmaceutical gel formulations. However, the mechanism pertaining to the stearic acid based gelation has not been deciphered yet. Keeping that in mind, we investigated the role of stearic acid on physic-chemical properties of oleogel. For this purpose, two different oil (sesame oil and soy bean oil) formulations/oleogels were prepared. In depth analysis of gel kinetics, gel microstructure, molecular interactions, thermal and mechanical behaviors of the oleogels were done. The properties of the oleogels were dependent on the type of the vegetable oil used and the concentration of the stearic acid. Avrami analysis of DSC thermograms indicated that heterogeneous nucleation was coupled with the one-dimensional growth of gelator fibers as the key phenomenon in the formation of oleogels. Viscoelastic and pseudoplastic nature of the oleogels was analyzed in-depth by fitting the stress relaxation data in modified Peleg's model and rheological studies, respectively. Textural studies have revealed that the coexistence of hydrogen bond dissipation and formation of new bonds is possible under stress conditions in the physical oleogels. PMID:25579972

  16. American Society of Nephrology Quiz and Questionnaire 2015: Electrolytes and Acid-Base Disorders.

    Rosner, Mitchell H; Perazella, Mark A; Choi, Michael J

    2016-04-01

    The Nephrology Quiz and Questionnaire remains an extremely popular session for attendees of the annual Kidney Week meeting of the American Society of Nephrology. During the 2015 meeting the conference hall was once again overflowing with eager quiz participants. Topics covered by the experts included electrolyte and acid-base disorders, glomerular disease, end-stage renal disease and dialysis, and kidney transplantation. Complex cases representing each of these categories together with single-best-answer questions were prepared and submitted by the panel of experts. Before the meeting, training program directors of nephrology fellowship programs and nephrology fellows in the United States answered the questions through an internet-based questionnaire. During the live session members of the audience tested their knowledge and judgment on the same series of case-oriented questions in a quiz. The audience compared their answers in real time using a cell-phone app containing the answers of the nephrology fellows and training program directors. The results of the online questionnaire were displayed, and then the quiz answers were discussed. As always, the audience, lecturers, and moderators enjoyed this highly educational session. This article recapitulates the session and reproduces selected content of educational value for theClinical Journal of the American Society of Nephrologyreaders. Enjoy the clinical cases and expert discussions. PMID:26825098

  17. Lipoamino acid-based micelles as promising delivery vehicles for monomeric amphotericin B.

    Serafim, Cláudia; Ferreira, Inês; Rijo, Patrícia; Pinheiro, Lídia; Faustino, Célia; Calado, António; Garcia-Rio, Luis

    2016-01-30

    Lipoamino acid-based micelles have been developed as delivery vehicles for the hydrophobic drug amphotericin B (AmB). The micellar solubilisation of AmB by a gemini lipoamino acid (LAA) derived from cysteine and its equimolar mixtures with the bile salts sodium cholate (NaC) and sodium deoxycholate (NaDC), as well as the aggregation sate of the drug in the micellar systems, was studied under biomimetic conditions (phosphate buffered-saline, pH 7.4) using UV-vis spectroscopy. Pure surfactant systems and equimolar mixtures were characterized by tensiometry and important parameters were determined, such as critical micelle concentration (CMC), surface tension at the CMC (γCMC), maximum surface excess concentration (Γmax), and minimum area occupied per molecule at the water/air interface (Amin). Rheological behaviour from viscosity measurements at different shear rates was also addressed. Solubilisation capacity was quantified in terms of molar solubilisation ratio (χ), micelle-water partition coefficient (KM) and Gibbs energy of solubilisation (ΔGs°). Formulations of AmB in micellar media were compared in terms of drug loading, encapsulation efficiency, aggregation state of AmB and in vitro antifungal activity against Candida albicans. The LAA-containing micellar systems solubilise AmB in its monomeric and less toxic form and exhibit in vitro antifungal activity comparable to that of the commercial formulation Fungizone. PMID:26617315

  18. First-principles study of physisorption of nucleic acid bases on small-diameter carbon nanotubes

    We report the results of our first-principles study based on density functional theory on the interaction of the nucleic acid base molecules adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U), with a single-walled carbon nanotube (CNT). Specifically, the focus is on the physisorption of base molecules on the outer wall of a (5, 0) metallic CNT possessing one of the smallest diameters possible. Compared to the case for CNTs with large diameters, the physisorption energy is found to be reduced in the high-curvature case. The base molecules exhibit significantly different interaction strengths and the calculated binding energies follow the hierarchy G>A>T>C>U, which appears to be independent of the tube curvature. The stabilizing factor in the interaction between the base molecule and CNT is dominated by the molecular polarizability that allows a weakly attractive dispersion force to be induced between them. The present study provides an improved understanding of the role of the base sequence in deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) in their interactions with carbon nanotubes of varying diameters

  19. New URJC-1 Material with Remarkable Stability and Acid-Base Catalytic Properties

    Pedro Leo

    2016-02-01

    Full Text Available Emerging new metal-organic structures with tunable physicochemical properties is an exciting research field for diverse applications. In this work, a novel metal-organic framework Cu(HIT(DMF0.5, named URJC-1, with a three-dimensional non-interpenetrated utp topological network, has been synthesized. This material exhibits a microporous structure with unsaturated copper centers and imidazole–tetrazole linkages that provide accessible Lewis acid/base sites. These features make URJC-1 an exceptional candidate for catalytic application in acid and base reactions of interest in fine chemistry. The URJC-1 material also displays a noteworthy thermal and chemical stability in different organic solvents of different polarity and boiling water. Its catalytic activity was evaluated in acid-catalyzed Friedel–Crafts acylation of anisole with acetyl chloride and base-catalyzed Knoevenagel condensation of benzaldehyde with malononitrile. In both cases, URJC-1 material showed very good performance, better than other metal organic frameworks and conventional catalysts. In addition, a remarkable structural stability was proven after several consecutive reaction cycles.

  20. High-molecular-weight polymers for protein crystallization: poly-γ-glutamic acid-based precipitants

    High-molecular-weight poly-γ-glutamic acid-based polymers have been synthesized, tested and adopted for protein crystallization. Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-γ-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of ∼400 kDa and PGA-HM (high molecular weight) of >1000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here

  1. Oleic acid based heterolipid synthesis, characterization and application in self-microemulsifying drug delivery system.

    Kalhapure, Rahul S; Akamanchi, Krishnacharya G

    2012-04-01

    There is increasing demand for lipids owing to their use in formulating lipid based drug delivery systems of poorly soluble drugs. The present work discusses the synthesis, characterization of oleic acid based heterolipid and its use as oil in the development of self-microemulsifying drug delivery system (SMEDDS) for parenteral delivery. Synthesis was carried out by Michael addition of tert-butyl acrylate to 3-amino-1-propanol to obtain di-tert-butyl aminopropanol derivative. Reaction of this di-tert-butyl aminopropanol derivative with oleoyl chloride using p-dimethylaminopyridine as a coupling agent gave the desired heterolipid. It was characterized by (1)H NMR, (13)C NMR and MS to confirm the structure. It did not exhibit any measurable cytotoxicity, even up to 80μg/ml concentration. Application in parenteral drug delivery was explored using furosemide (FUR), a BCS class IV drug, as a model. FUR showed three times greater solubility in the heterolipid as compared to oleic acid. SMEDDSs were developed using heterolipid as oily phase, Solutol HS 15(®) as surfactant and ethanol as a co-surfactant. Developed SMEDDS could form spontaneous microemulsion on addition to various aqueous phases with mean globule size <70nm without any phase separation or drug precipitation even after 24h, and exhibited negligible hemolytic potential. PMID:22266534

  2. High-molecular-weight polymers for protein crystallization: poly-γ-glutamic acid-based precipitants

    Hu, Ting-Chou [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Korczyńska, Justyna [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Structural Biology Laboratory, University of York, York YO10 5YW (United Kingdom); Smith, David K. [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Brzozowski, Andrzej Marek, E-mail: marek@ysbl.york.ac.uk [Department of Chemistry, University of York, York YO10 5YW (United Kingdom); Structural Biology Laboratory, University of York, York YO10 5YW (United Kingdom)

    2008-09-01

    High-molecular-weight poly-γ-glutamic acid-based polymers have been synthesized, tested and adopted for protein crystallization. Protein crystallization has been revolutionized by the introduction of high-throughput technologies, which have led to a speeding up of the process while simultaneously reducing the amount of protein sample necessary. Nonetheless, the chemistry dimension of protein crystallization has remained relatively undeveloped. Most crystallization screens are based on the same set of precipitants. To address this shortcoming, the development of new protein precipitants based on poly-γ-glutamic acid (PGA) polymers with different molecular-weight ranges is reported here: PGA-LM (low molecular weight) of ∼400 kDa and PGA-HM (high molecular weight) of >1000 kDa. It is also demonstrated that protein precipitants can be expanded further to polymers with much higher molecular weight than those that are currently in use. Furthermore, the modification of PGA-like polymers by covalent attachments of glucosamine substantially improved their solubility without affecting their crystallization properties. Some preliminary PGA-based screens are presented here.

  3. Kidney injury, fluid, electrolyte and acid-base abnormalities in alcoholics

    Adebayo Adewale

    2014-01-01

    Full Text Available In the 21 st century, alcoholism and the consequences of ethyl alcohol abuse are major public health concerns in the United States, affecting approximately 14 million people. Pertinent to the global impact of alcoholism is the World Health Organisation estimate that 140 million people worldwide suffer from alcohol dependence. Alcoholism and alcohol abuse are the third leading causes of preventable death in the United States. Alcohol dependence and alcohol abuse cost the United State an estimated US$220 billion in 2005, eclipsing the expense associated with cancer (US$196 billion or obesity (US$133 billion. Orally ingested ethyl alcohol is absorbed rapidly without chemical change from the stomach and intestine, reaching maximum blood concentration in about an hour. Alcohol crosses capillary membranes by simple diffusion, affecting almost every organ system in the body by impacting a wide range of cellular functions. Alcohol causes metabolic derangements either directly, via its chemical by-product or secondarily through alcohol-induced disorders. Many of these alcohol-related metabolic disturbances are increased in severity by the malnutrition that is common in those with chronic alcoholism. This review focuses on the acute and chronic injurious consequences of alcohol ingestion on the kidney, as well as the fluid, electrolyte and acid-base abnormalities associated with acute and chronic ingestion of alcohol.

  4. FERTILIZATION OF VINE BY A 5-AMINOLEVULINIC ACID-BASED FERTILIZER AND ITS PROFITABILITY

    VLADIMR IMANSK

    2013-03-01

    Full Text Available In this work we investigated the effect of different doses of NPKS fertilizer added into the soil for nutrient contents in the soil, as well as the quantity and quality of grapes. During the vegetation of the vine, we tested the 5-aminolevulinic acid-based fertilizer (ALA. We summarize that higher doses of fertilizer added into soil caused higher amounts of available nutrients. During the vegetation of the vine an increase of ALA had a positive effect on the optimal balance of nutrients. Fertilization also increased the grape-vine yield, with the strongest effect (by 68% observed due to the application of ALA during the vegetation period of the vine. Added fertilizers had a statistically significant influence on decreased sugar concentration in the grape-vine however the addition of fertilizer into the soil, mainly the application of ALA during vegetation of the vine (by 57% had a positive effect on increase of the total content of sugar in the grape-vine, produced on 1 hectare. The year had a significant influence on the economical evaluation.

  5. Biodiesel Production from Spent Fish Frying Oil Through Acid-Base Catalyzed Transesterification

    Abdalrahman B. Fadhil

    2012-06-01

    Full Text Available Biodiesel fuels were prepared from a special type of frying oil namely spent fish frying oil through two step transesterification viz. acid-base catalyzed transesterification. Hydrochloric acid and potassium hydroxide with methanol were used for this purpose. The oil was pre-treated with (1.0 wt% HCl and methanol to reduce free fatty acids content of the oil. Then, conditions of the base catalyzed step such as base concentration, reaction temperature, methanol to oil molar ratio and reaction time were optimized. The study raveled that, 0.50% KOH w/w of oil; a 6:1 methanol to oil molar ratio; a reaction temperature of 60°C and a duration of 1h were the optimal conditions because they resulted in high biodiesel yield. Fuel properties of the products were assessed and found better than those of the parent oil. Furthermore, they met the specified limits according to the ASTM standards. Thin layer chromatography was used as a simple technique to monitor the transesterification of the oil. Blending of the optimal biodiesel sample with petro diesel using specified volume percentages was done as well. The results indicated that biodiesel had slight effect on the values of the assessed properties.

  6. Study of equilibrium using collision dynamics

    Full text: The heavy-ion collisions at low, intermediate and relativistic energies provide a unique possibility to investigate the different questions ranging from the fusion at low incident energies to the formation of quark-gluon-plasma at higher incident energies. The intermediate energy heavy-ion collisions are excellent tool to study the nuclear equation of state which depends on the temperature as well on the density of the matter. Another important question associated with heavy-ion collision is the degree of equilibrium reached in a reaction. The answer of this question is important as there are several models employed at intermediate energy that assume global (or local) equilibrium. We shall study this question with two different aims. First, we would like to see whether a equilibrium is reached in a heavy-ion collision or not. Secondly, one is interested to know the number of collisions one needs to thermalized the matter. This study is attempted within Quantum Molecular Dynamics (QMD) model [1]. The QMD model is based on molecular dynamics picture where nucleons propagate under the influence of two and three body interactions. Here nucleon-nucleon potential is represented by the Skyrme, Coulomb and Yukawa forces. The question of equilibrium is addressed with the help of rapidity distribution which is defined as: Yi = 1/2 Ln E(i) + pz (i) c / E(i) - pz (i) c Here E(i) and pz(i) denote, respectively, the total energy and longitudinal momentum of the with particle. For a complete equilibrium, one should get a single peak in the distribution at mid rapidity. We calculated the rapidity distribution of Sn-Xe reaction at incident of 50, 400 and 2000 MeV/nucleon. We find that central collisions lead to better global equilibrium whereas peripheral collisions lack equilibrium. Further, one needs 10 collisions for complete equilibrium i.e. for a single peak at mid rapidity distribution. Whereas, if the number of collisions is less than 10, one obtains two peaks

  7. Torque equilibrium attitude control for Skylab reentry

    Glaese, J. R.; Kennel, H. F.

    1980-01-01

    The method of torque equilibrium attitude control used to control the reentry of Skylab to an altitude below 150 km without the use of thruster fuel once the attitude was established is discussed. The Skylab attitude and pointing control system, which included rate gyros, sun sensors, star tracker, the Apollo telescope mount digital computer, control moment gyros and cold-gas attitude thrusters, is presented. The 12 torque equilibrium attitudes found at which aerodynamic, gravity gradient and gyroscopic torques would balance are indicated, and the three of those at which the solar power supply would be adequate for attitude control are illustrated. The equilibrium seeking method employed is then examined, and the operation and performance of the torque equilibrium attitude control system during the three weeks prior to Skylab reentry are discussed. It is concluded that the torque equilibrium attitude control method developed for Skylab was successful in performing its assigned mission, and will be valuable for the design of future, low-altitude spacecraft or tethered vehicles.

  8. Planetary cratering 2: Studies of saturation equilibrium

    Hartmann, William K.; Gaskell, Robert W.

    1997-01-01

    A realistic computer model has been developed to display images of imaginary cratered surfaces, taking into account empirically measured input size distributions of primary and secondary craters, ejecta blanket morphology including feathering with distance, obliteration due to ejecta from outside the imaged area, lighting effects, etc. The model allows us to track surface evolution of morphology as new craters are added. Using the model as well as lunar photos, we have studied the approach to saturation equilibrium (defined as a condition when no further proportionate increase in crater density occurs as input cratering increases). We find that an identifiable saturation equilibrium occurs close to a level previously identified for this state (Hartmann 1984), typically fluctuating around a crater density from about 0.4 to 2 times that level. This result is fairly robust vis-a-vis the range of model parameters we have chosen. Flooding, basin ejecta blankets, and other obliterative effects can introduce structure and oscillations within this range, even after saturation equilibrium is achieved. These findings may constrain or revise certain earlier interpretations of satellite and planet surface evolution and impactor populations which were predicated on the assumed absence of saturation equilibrium. In our fourth experimental run, we found that suppression of "sandblasting" by sub-resolution impacts allows the smallest secondaries to rise above the saturation equilibrium line, a result that might be relevant to a similar situation on Gaspra and perhaps some other asteroids.

  9. C-3-symmetric, amino acid based organogelators and thickeners : a systematic study of structure-property relations

    de Loos, Maaike; van Esch, Jan H.; Kellogg, Richard M.; Feringa, Ben L.

    2007-01-01

    A class of C-3-symmetric amino acid based organogelators and thickeners featuring a rigid core have been developed. Structural variation yielded a number of compounds, the aggregation behaviour and resulting aggregates and gels of which were studied by FTIR spectroscopy, dropping ball measurements,

  10. Development and Evaluation of a Multimedia e-Learning Resource for Electrolyte and Acid-Base Disorders

    Davids, Mogamat Razeen; Chikte, Usuf M. E.; Halperin, Mitchell L.

    2011-01-01

    This article reports on the development and evaluation of a Web-based application that provides instruction and hands-on practice in managing electrolyte and acid-base disorders. Our teaching approach, which focuses on concepts rather than details, encourages quantitative analysis and a logical problem-solving approach. Identifying any dangers to…

  11. Non-equilibrium quantum heat machines

    Alicki, Robert; Gelbwaser-Klimovsky, David

    2015-11-01

    Standard heat machines (engine, heat pump, refrigerator) are composed of a system (working fluid) coupled to at least two equilibrium baths at different temperatures and periodically driven by an external device (piston or rotor) sometimes called the work reservoir. The aim of this paper is to go beyond this scheme by considering environments which are stationary but cannot be decomposed into a few baths at thermal equilibrium. Such situations are important, for example in solar cells, chemical machines in biology, various realizations of laser cooling or nanoscopic machines driven by laser radiation. We classify non-equilibrium baths depending on their thermodynamic behavior and show that the efficiency of heat machines powered by them is limited by the generalized Carnot bound.

  12. Non-Equilibrium Thermodynamics in Multiphase Flows

    Mauri, Roberto

    2013-01-01

    Non-equilibrium thermodynamics is a general framework that allows the macroscopic description of irreversible processes. This book introduces non-equilibrium thermodynamics and its applications to the rheology of multiphase flows. The subject is relevant to graduate students in chemical and mechanical engineering, physics and material science. This book is divided into two parts. The first part presents the theory of non-equilibrium thermodynamics, reviewing its essential features and showing, when possible, some applications. The second part of this book deals with how the general theory can be applied to model multiphase flows and, in particular, how to determine their constitutive relations. Each chapter contains problems at the end, the solutions of which are given at the end of the book. No prior knowledge of statistical mechanics is required; the necessary prerequisites are elements of transport phenomena and on thermodynamics. “The style of the book is mathematical, but nonetheless it remains very re...

  13. Computational studies in tokamak equilibrium and transport

    This thesis is concerned with some problems arising in the magnetic confinement approach to controlled thermonuclear fusion. The work address the numerical modelling of equilibrium and transport properties of a confined plasma and the interpretation of experimental data. The thesis is divided in two parts. Part 1 is devoted to some aspects of the MHD equilibrium problem, both in the 'direct' formulation (given an equation for the plasma current, the corresponding equilibrium is to be determined) and in the 'inverse' formulation (the interpretation of measurements at the plasma edge). Part 2 is devoted to numerical studies of the edge plasma. The appropriate Navier-Stokes system of fluid equations is solved in a two-dimensional geometry. The main interest of this work is to develop an understanding of particle and energy transport in the scrape-off layer and onto material boundaries, and also to contribute to the conceptual design of the NET/INTOR tokamak reactor experiment. (Auth.)

  14. Module description of TOKAMAK equilibrium code MEUDAS

    The analysis of an axisymmetric MHD equilibrium serves as a foundation of TOKAMAK researches, such as a design of devices and theoretical research, the analysis of experiment result. For this reason, also in JAERI, an efficient MHD analysis code has been developed from start of TOKAMAK research. The free boundary equilibrium code ''MEUDAS'' which uses both the DCR method (Double-Cyclic-Reduction Method) and a Green's function can specify the pressure and the current distribution arbitrarily, and has been applied to the analysis of a broad physical subject as a code having rapidity and high precision. Also the MHD convergence calculation technique in ''MEUDAS'' has been built into various newly developed codes. This report explains in detail each module in ''MEUDAS'' for performing convergence calculation in solving the MHD equilibrium. (author)

  15. Module description of TOKAMAK equilibrium code MEUDAS

    Suzuki, Masaei; Hayashi, Nobuhiko; Matsumoto, Taro; Ozeki, Takahisa [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    2002-01-01

    The analysis of an axisymmetric MHD equilibrium serves as a foundation of TOKAMAK researches, such as a design of devices and theoretical research, the analysis of experiment result. For this reason, also in JAERI, an efficient MHD analysis code has been developed from start of TOKAMAK research. The free boundary equilibrium code ''MEUDAS'' which uses both the DCR method (Double-Cyclic-Reduction Method) and a Green's function can specify the pressure and the current distribution arbitrarily, and has been applied to the analysis of a broad physical subject as a code having rapidity and high precision. Also the MHD convergence calculation technique in ''MEUDAS'' has been built into various newly developed codes. This report explains in detail each module in ''MEUDAS'' for performing convergence calculation in solving the MHD equilibrium. (author)

  16. Perturbative Non-Equilibrium Thermal Field Theory

    Millington, Peter

    2013-01-01

    We present a new perturbative formulation of non-equilibrium thermal field theory, based upon non-homogeneous free propagators and time-dependent vertices. Our approach to non-equilibrium dynamics yields time-dependent diagrammatic perturbation series that are free of pinch singularities, without the need to resort to quasi-particle approximation or effective resummations of finite widths. In our formalism, the avoidance of pinch singularities is a consequence of the consistent inclusion of finite-time effects and the proper consideration of the time of observation. After introducing a physically meaningful definition of particle number densities, we derive master time evolution equations for statistical distribution functions, which are valid to all orders in perturbation theory. The resulting equations do not rely upon a gradient expansion of Wigner transforms or involve any separation of time scales. To illustrate the key features of our formalism, we study out-of-equilibrium decay dynamics of unstable par...

  17. Correlation between the acid-base properties of the La2O3 catalyst and its methane reactivity.

    Chu, Changqing; Zhao, Yonghui; Li, Shenggang; Sun, Yuhan

    2016-06-28

    Density functional theory and coupled cluster theory calculations were carried out to study the effects of the acid-base properties of the La2O3 catalyst on its catalytic activity in the oxidative coupling of methane (OCM) reaction. The La(3+)-O(2-) pair site for CH4 activation is considered as a Lewis acid-Brönsted base pair. Using the Lewis acidity and the Brönsted basicity in the fluoride affinity and proton affinity scales as quantitative measures of the acid-base properties, the energy barrier for CH4 activation at the pair site can be linearly correlated with these acid-base properties. The pair site consisting of a strong Lewis acid La(3+) site and a strong Brönsted base O(2-) site is the most reactive for CH4 activation. In addition, the basicity of the La2O3 catalyst was traditionally measured by temperature-programmed desorption of CO2, but the CO2 chemisorption energy is better regarded as a combined measure of the acid-base properties of the pair site. A linear relationship of superior quality was found between the energy barrier for CH4 activation and the CO2 chemisorption energy, and the pair site favorable for CO2 chemisorption is also more reactive for CH4 activation, leading to the conflicting role of the "basicity" of the La2O3 catalyst in the OCM reaction. The necessity for very high reaction temperatures in the OCM reaction is rationalized by the requirement for the recovery of the most reactive acid-base pair site, which unfortunately also reacts most readily with the byproduct CO2 to form the very stable CO3(2-) species. PMID:27265027

  18. Putting A Human Face on Equilibrium

    Glickstein, Neil

    2005-03-01

    A short biography of chemist Fritz Haber is used to personalize the abstract concepts of equilibrium chemistry for high school students in an introductory course. In addition to giving the Haber Bosch process an historic, an economic, and a scientific background the reading and subsequent discussion allows students for whom the human perspective is of paramount importance a chance to investigate the irony of balance or equilibrium in Haber's life story. Since the inclusion of the Haber biography, performance in the laboratory and on examinations for those students who are usually only partially engaged has dramatically improved.

  19. Equilibrium under uncertainty with Sugeno payoff

    Radul, Taras

    2015-01-01

    This paper studies n-player games where players beliefs about their opponents behaviour are capacities. The concept of an equilibrium under uncertainty was introduced J.Dow and S.Werlang (J Econ. Theory 64 (1994) 205--224) for two players and was extended to n-player games by J.Eichberger and D.Kelsey (Games Econ. Behav. 30 (2000) 183--215). Expected utility was expressed by Choquet integral. We consider the concept of an equilibrium under uncertainty in this paper but with expected utility e...

  20. Absence of equilibrium chiral magnetic effect

    Zubkov, M A

    2016-01-01

    We analyse the $3+1$ D equilibrium chiral magnetic effect (CME). We apply derivative expansion to the Wigner transform of the two - point Green function. This technique allows us to express the response of electric current to external electromagnetic field strength through the momentum space topological invariant. We consider the wide class of the lattice regularizations of quantum field theory (that includes, in particular, the regularization with Wilson fermions) and also certain lattice models of solid state physics (including those of Dirac semimetals). It appears, that in these models the mentioned topological invariant vanishes identically at nonzero chiral chemical potential. That means, that the bulk equilibrium CME is absent in those systems.

  1. Equilibrium stellar systems with genetic algorithms

    Gularte, E.; Carpintero, D. D.

    In 1979, M Schwarzschild showed that it is possible to build an equilibrium triaxial stellar system. However, the linear programmation used to that goal was not able to determine the uniqueness of the solution, nor even if that solution was the optimum one. Genetic algorithms are ideal tools to find a solution to this problem. In this work, we use a genetic algorithm to reproduce an equilibrium spherical stellar system from a suitable set of predefined orbits, obtaining the best solution attainable with the provided set. FULL TEXT IN SPANISH

  2. In Search of Equilibrium: Containers of Light.

    Kamat, Smruti

    2004-01-01

    The goal of this thesis is to find that point of equilibrium in a composition where nothing can be added and nothing can be taken away. Each and every element is vital and any addition or subtraction will disturb this equilibrium. The nature of this investigation requires a program where simplicity is a virtue. The word temple is derived from 'temnere', which means to cut, to take away. I understand this as a process of subtracting to create meaning out of something that would otherwise h...

  3. Far-from-equilibrium kinetic processes

    Rubí, J. Miguel; Pérez-Madrid, Agustin

    2015-12-01

    We analyze the kinetics of activated processes that take place under far-from-equilibrium conditions, when the system is subjected to external driving forces or gradients or at high values of affinities. We use mesoscopic non-equilibrium thermodynamics to show that when a force is applied, the reaction rate depends on the force. In the case of a chemical reaction at high affinity values, the reaction rate is no longer constant but depends on affinity, which implies that the law of mass action is no longer valid. This result is in good agreement with the kinetic theory of reacting gases, which uses a Chapman-Enskog expansion of the probability distribution.

  4. Micro Data and General Equilibrium Models

    Browning, Martin; Hansen, Lars Peter; Heckman, James J.

    1999-01-01

    Dynamic general equilibrium models are required to evaluate policies applied at the national level. To use these models to make quantitative forecasts requires knowledge of an extensive array of parameter values for the economy at large. This essay describes the parameters required for different...... economic models, assesses the discordance between the macromodels used in policy evaluation and the microeconomic models used to generate the empirical evidence. For concreteness, we focus on two general equilibrium models: the stochastic growth model extended to include some forms of heterogeneity...

  5. Equilibrium calculations for helical axis stellarators

    An average method based on a vacuum flux coordinate system is presented. This average method permits the study of helical axis stellarators with toroidally dominated shifts. An ordering is introduced, and to lowest order the toroidally averaged equilibrium equations are reduced to a Grad-Shafranov equation. Also, to lowest order, a Poisson-type equation is obtained for the toroidally varying corrections to the equilibium. By including these corrections, systems that are toroidally dominated, but with significant helical distortion to the equilibrium, may be studied. Numerical solutions of the average method equations are shown to agree well with three-dimensional calculations

  6. General Equilibrium Pricing with Information Asymmetry

    Yuzhong eZhang

    2015-08-01

    Full Text Available We propose a general equilibrium model for asset pricing that incorporates asymmetric information as the key element determining security prices. In our setting, the concepts of completeness, arbitrage, state price and equivalent martingale measure are extended to the case of asymmetric information. Our model shows that in a so-called quasi-complete market, the agents with differential information can reach an agreement on an universal equilibrium price. The corresponding state price and martingale measure are determined. The key intuition is that agents evaluate consumption choices conditioned on their private information and the public information generated by price. As a consequence, information asymmetry can lead to mispricing as well.

  7. Correlating multidimensional fetal heart rate variability analysis with acid-base balance at birth.

    Frasch, Martin G; Xu, Yawen; Stampalija, Tamara; Durosier, Lucien D; Herry, Christophe; Wang, Xiaogang; Casati, Daniela; Seely, Andrew Je; Alfirevic, Zarko; Gao, Xin; Ferrazzi, Enrico

    2014-12-01

    Fetal monitoring during labour currently fails to accurately detect acidemia. We developed a method to assess the multidimensional properties of fetal heart rate variability (fHRV) from trans-abdominal fetal electrocardiogram (fECG) during labour. We aimed to assess this novel bioinformatics approach for correlation between fHRV and neonatal pH or base excess (BE) at birth.We enrolled a prospective pilot cohort of uncomplicated singleton pregnancies at 38-42 weeks' gestation in Milan, Italy, and Liverpool, UK. Fetal monitoring was performed by standard cardiotocography. Simultaneously, with fECG (high sampling frequency) was recorded. To ensure clinician blinding, fECG information was not displayed. Data from the last 60 min preceding onset of second-stage labour were analyzed using clinically validated continuous individualized multiorgan variability analysis (CIMVA) software in 5 min overlapping windows. CIMVA allows simultaneous calculation of 101 fHRV measures across five fHRV signal analysis domains. We validated our mathematical prediction model internally with 80:20 cross-validation split, comparing results to cord pH and BE at birth.The cohort consisted of 60 women with neonatal pH values at birth ranging from 7.44 to 6.99 and BE from -0.3 to -18.7 mmol L(-1). Our model predicted pH from 30 fHRV measures (R(2) = 0.90, P base balance at birth. Further refinement and validation in larger cohorts are needed. These new measurements of fHRV might offer a new opportunity to predict fetal acid-base balance at birth. PMID:25407948

  8. Amino acid-based surfactants – do they deserve more attention?

    Bordes, Romain; Holmberg, Krister

    2015-08-01

    The 20 standard amino acids (together with a few more that are not used in the biosynthesis of proteins) constitute a versatile tool box for synthesis of surfactants. Anionic, cationic and zwitterionic amphiphiles can be prepared and surfactants with several functional groups can be obtained by the proper choice of starting amino acid. This review gives examples of procedures used for preparation and discusses important physicochemical properties of the amphiphiles and how these can be taken advantage of for various applications. Micelles with a chiral surface can be obtained by self-assembly of enantiomerically pure surfactants and such supramolecular chirality can be utilized for asymmetric organic synthesis and for preparation of mesoporous materials with chiral pores. Surfactants based on amino acids with two carboxyl groups are effective chelating agents and can be used as collectors in mineral ore flotation. A surfactant based on cysteine readily oxidizes into the corresponding cystine compound, which can be regarded as a gemini surfactant. The facile and reversible cysteine-cystine transformation has been taken advantage of in the design of a switchable surfactant. A very attractive aspect of surfactants based on amino acids is that the polar head-group is entirely natural and that the linkage to the hydrophobic tail, which is often an ester or an amide bond, is easily cleaved. The rate of degradation can be tailored by the structure of the amphiphile. The ester linkage in betaine ester surfactants is particularly susceptible to alkaline hydrolysis and this surfactant type can be used as a biocide with short-lived action. This paper is not intended as a full review on the topic. Instead it highlights concepts that are unique to amino acid-based surfactants and that we believe can have practical implications. PMID:25846628

  9. Acid-base controllable recognition properties of a highly versatile calix[6]crypturea.

    Ménand, Mickaël; Jabin, Ivan

    2010-02-15

    Versatile concave receptors with binding properties that can be controlled by external stimuli are rare. Herein, we report on a calix[6]crypturea (1) that features two different binding sites in close proximity, that is, a tris(2-aminoethyl)amine (tren)-based tris-ureido cap that provides convergent hydrogen-bond-donor sites and a hydrophobic cavity suitable for the inclusion of organic guests. The binding properties of this heteroditopic receptor have been evaluated by NMR spectroscopic studies. Compound 1 behaves as a remarkably versatile host that strongly binds neutral molecules, anions, or contact ion pairs. Within each family of guests, compound 1 is able to discriminate between different guests with a high degree of selectivity. Indeed, neutral molecules that possess hydrogen-bond donor and acceptor groups, chloride anions, and linear ammonium ions associated to F(-) or Cl(-) are particularly well recognized. In comparison with all the related receptors, compound 1 displays several unique features: 1) charged or neutral species are also recognized in polar or protic solvents, 2) thanks to the flexibility of the calixarene structure, induced-fit processes allow the binding of large, biologically relevant ammonium salts such as neurotransmitters, and 3) the protonation of the basic cap leads to a positively charged receptor, 1.H(+), which is reluctant to host anions and in which host properties are now governed by strong charge-dipole interactions with the guests. In other words, compound 1 presents an acid-base controllable tris-ureido recognition site protected by a hydrophobic corridor that can select guests through induced-fit processes. Thus, its versatile host properties can be allosterically controlled by protonation and selective guest-switching processes are possible. To illustrate all these remarkable features, a sophisticated three-pole supramolecular switch, based on the interconversion of host-guest systems displaying either charged or neutral

  10. The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran

    Jokić Anja B.

    2013-01-01

    Full Text Available The application of the hydrogen-palladium electrode (H2/Pd as the indicator electrode for the determination of relative acidity scale (Es, mV of tetrahydrofuran (THF and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH, which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051

  11. Equilibrium shapes of a ferrofluid drop

    Lavrova, O.; Polevikov, V.; Tobiska, L.

    2005-01-01

    A numerical solution strategy for calculating equilibrium free surfaces of a ferrofluid drop under the action of uniform magnetic fields is proposed. Based on this strategy, drop shapes of nonlinear magnetizable fluids are obtained numerically in a wide range of field intensities and compared with existing theoretical results

  12. Non-equilibrium thermodynamics and physical kinetics

    Bikkin, Halid

    2014-01-01

    This graduate textbook covers contemporary directions of non-equilibrium statistical mechanics as well as classical methods of kinetics. With one of the main propositions being to avoid terms such as "obviously" and "it is easy to show", this treatise is an easy-to-read introduction into this traditional, yet vibrant field.

  13. The Foundations of Computable General Equilibrium Theory

    Velupillai, K. Vela

    2005-01-01

    A constructive and recursion theoretic analysis of the standard Computable General Equilibrium (CGE) model of economic theory is undertaken. It is shown, contrary to widely expressed views and textbook versions of the CGE model, that the standard CGE model is neither computable nor constructive in the strict mathematical senses.

  14. Perfect Bayesian equilibrium. Part II: epistemic foundations

    Bonanno, Giacomo

    2011-01-01

    In a companion paper we introduced a general notion of perfect Bayesian equilibrium which can be applied to arbitrary extensive-form games. The essential ingredient of the proposed definition is the qualitative notion of AGM-consistency. In this paper we provide an epistemic foundation for AGM-consistency based on the AGM theory of belief revision.

  15. Exploring Equilibrium Chemistry for Hot Exoplanets

    Blumenthal, Sarah; Harrington, Joseph; Mandell, Avi; Hébrard, Eric; Venot, Olivia; Cubillos, Patricio; Challener, Ryan

    2015-11-01

    It has been established that equilibrium chemistry is usually achieved deep in the atmosphere of hot Jovians where timescales are short (Line and Young 2013). Thus, equilibrium chemistry has been used as a starting point (setting initial conditions) for evaluating disequilibrium processes. We explore parameters of setting these initial conditions including departures from solar metallicity, the number of species allowed in a system, the types of species allowed in a system, and different thermodynamic libraries in an attempt to create a standard for evaluating equilibrium chemistry. NASA's open source code Chemical Equilibrium and Applications (CEA) is used to calculate model planet abundances by varying the metallicity, in the pressure regime of 0.1 to 1 bar. These results are compared to a variety of exoplanets (Teq between 600 and 2100K) qualitatively by color maps of the dayside with different temperature redistributions. Additionally, CEA (with an updated thermodynamic library) is validated with the thermochemical model presented in Venot et al. (2012) for HD 209458b and HD 189733b. This same analysis has then been extended to the cooler planet HD 97658b. Spectra are generated from both models’ abundances using the open source code transit (https://github.com/exosports/transit) using the opacities of 15 molecules. We make the updated CEA thermodyanamic library and supporting Python scripts to do the CEA analyses available open source. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G.

  16. Identification of Dynamic Stochastic General Equilibrium Models

    Morris, Stephen David

    2014-01-01

    The dissertation "Identification of Dynamic Stochastic General Equilibrium Models" by Stephen David Morris is divided into three chapters. The first chapter considers the statistical implications of common identifying restrictions for DSGE models. The second chapter considers the implications of identification failure for Bayesian estimators. The third chapter considers how identification of nonlinear solutions compares with that of linear solutions

  17. Punctuated equilibrium in an evolving bacterial population

    Chaudhuri, Indranath; Bose, Indrani

    1999-01-01

    Recently, Lenski et al have carried out an experiment on bacterial evolution. Their findings support the theory of punctuated equilibrium in biological evolution. We show that the M=2 Bak-Sneppen model can explain some of the experimental results in a qualitative manner.

  18. Neutrino transport: no asymmetry in equilibrium

    Kusenko, Alexander; Segre, Gino; Vilenkin, Alexander

    1998-01-01

    A small asymmetry in the flux of neutrinos emitted by a hot newly-born neutron star could explain the observed motions of pulsars. However, even in the presence of parity-violating processes with anisotropic scattering amplitudes, no asymmetry is generated in thermal equilibrium. We explain why this no-go theorem stymies some of the proposed explanations for the pulsar ``kick'' velocities.

  19. Exploring Chemical Equilibrium in Hot Jovians

    Blumenthal, Sarah; Harrington, Joseph; Mandell, Avi; Hébrard, Eric; Venot, Olivia; Cubillos, Patricio; Blecic, Jasmina; Challener, Ryan

    2016-01-01

    It has been established that equilibrium chemistry is usually achieved deep in the atmosphere of hot Jovians where timescales are short (Line and Yung 2013). Thus, equilibrium chemistry has been used as a starting point (setting initial conditions) for evaluating disequilibrium processes. We explore parameters of setting these initial conditions including departures from solar metallicity, the number of species allowed in a system, the types of species allowed in a system, and different thermodynamic libraries in an attempt to create a standard for evaluating equilibrium chemistry. NASA's open source code Chemical Equilibrium and Applications (CEA) is used to calculate model planet abundances by varying the metallicity, in the pressure regime 0.1 to 1 bar. These results are compared to a variety of exoplanets(Teq between 600 and 2100K) qualitatively by color maps of the dayside with different temperature redistributions. Additionally, CEA (with an up-dated thermodynamic library) is compared with the thermochemical model presented in Venotet al. (2012) for HD 209458b and HD 189733b. This same analysis is then applied to the cooler planet HD 97658b. Spectra are generated and we compare both models' outputs using the open source codetransit (https://github.com/exosports/transit) using the opacities of 15 molecules. We make the updated CEA thermodyanamic library and supporting Python scripts to do the CEA analyses available open source. Thiswork was supported by NASA Planetary Atmospheres grant NNX12AI69G.

  20. General Equilibrium Models: Improving the Microeconomics Classroom

    Nicholson, Walter; Westhoff, Frank

    2009-01-01

    General equilibrium models now play important roles in many fields of economics including tax policy, environmental regulation, international trade, and economic development. The intermediate microeconomics classroom has not kept pace with these trends, however. Microeconomics textbooks primarily focus on the insights that can be drawn from the…

  1. Testable Restrictions on the Equilibrium Manifold

    Brown, Donald J.; Rosa L. Matzkin

    1995-01-01

    We present a finite system of polynomial inequalities in unobservable variables and market data that observations on market prices, individual incomes and aggregate endowments must satisfy to be consistent with the equilibrium behavior of some pure trade economy. Quantifier elimination is used to derive testable propositions on finite data sets for the pure trade model.

  2. Estimating Equilibrium Effects of Job Search Assistance

    Gautier, Pieter; Muller, Paul; van der Klaauw, Bas; Rosholm, Michael; Svarer, Michael

    nonparticipants in the experiment regions find jobs slower after the introduction of the activation program (relative to workers in other regions). We then estimate an equilibrium search model. This model shows that a large scale role out of the activation program decreases welfare, while a standard partial...... microeconometric cost-benefit analysis would conclude the opposite....

  3. Specialization and Human Capital in Search Equilibrium

    Mukoyama, Toshihiko; Şahin, Ayşegül

    2005-01-01

    This paper constructs a general equilibrium search-matching model with heterogeneous workers. Workers choose whether to invest in general human capital or specific human capital when they enter the labor market. We analyze how unemployment benefits affect the choice of the type of human capital investment.

  4. An analysis of the concept of equilibrium in organization theory

    Gazendam, Henk W.M.; Simons, John L.

    1998-01-01

    This article analyzes how the equilibrium concept is used in four organization theories: the theories of Fayol, Mintzberg, Morgan, and Volberda. Equilibrium can be defined as balance, fit or requisite variety. Equilibrium is related to observables dependent on the definition of organization as work organization, formal organization or artifact organization. The discussed theories can be mapped on a state space model in a way that clarifies the equilibrium concept. The equilibrium concept in o...

  5. Effective equilibrium theory of nonequilibrium quantum transport

    The theoretical description of strongly correlated quantum systems out of equilibrium presents several challenges and a number of open questions persist. Here, we focus on nonlinear electronic transport through an interacting quantum dot maintained at finite bias using a concept introduced by Hershfield [S. Hershfield, Phys. Rev. Lett. 70 2134 (1993)] whereby one can express such nonequilibrium quantum impurity models in terms of the system's Lippmann-Schwinger operators. These scattering operators allow one to reformulate the nonequilibrium problem as an effective equilibrium problem associated with a modified Hamiltonian. In this paper, we provide a pedagogical analysis of the core concepts of the effective equilibrium theory. First, we demonstrate the equivalence between observables computed using the Schwinger-Keldysh framework and the effective equilibrium approach, and relate Green's functions in the two theoretical frameworks. Second, we expound some applications of this method in the context of interacting quantum impurity models. We introduce a novel framework to treat effects of interactions perturbatively while capturing the entire dependence on the bias voltage. For the sake of concreteness, we employ the Anderson model as a prototype for this scheme. Working at the particle-hole symmetric point, we investigate the fate of the Abrikosov-Suhl resonance as a function of bias voltage and magnetic field. - Highlights: → Reformulation of steady-state nonequilibrium quantum transport, following Hershfield. → Derivation of effective equilibrium density operator using the 'open-system' approach. → Equivalence with the Keldysh description and formulas relating the two approaches. → Novel framework to treat interactions perturbatively. → Application to nonequilibrium Anderson model and fate of Abrikosov-Suhl resonance.

  6. Standardization of 125 Sb in equilibrium non-equilibrium situations with 125m Te

    We study the stability of ''125 Sb in the following scintillators: HiSafeIII''TM, Insta- Gel regsign Plus and '' Ultima-Gold'' TM. Since ''125 m Te requires more than one year to reach the secular equilibrium with ''125 Sb, we cannot be sure, for a given sample, whether equilibrium is reached or not. In this report we present a new procedure that permits one calibrate mixtures of ''125 Sb+''125 m Te out of the equilibrium. The steps required for the radiochemical separation of the components are indicated. Finally, we study the evolution of counting rate when column yields are less than 100%. (Author)

  7. Metabolic fate of poly-(lactic-co-glycolic acid-based curcumin nanoparticles following oral administration

    Harigae T

    2016-06-01

    Full Text Available Takahiro Harigae,1 Kiyotaka Nakagawa,1 Taiki Miyazawa,2 Nao Inoue,3 Fumiko Kimura,1 Ikuo Ikeda,3 Teruo Miyazawa4,5 1Food and Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan; 2Vascular Biology Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA; 3Laboratory of Food and Biomolecular Science, Graduate School of Agricultural Science, 4Food and Biotechnology Innovation Project, New Industry Creation Hatchery Center, 5Food and Health Science Research Unit, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan Purpose: Curcumin (CUR, the main polyphenol in turmeric, is poorly absorbed and rapidly metabolized following oral administration, which severely curtails its bioavailability. Poly-(lactic-co-glycolic acid-based CUR nanoparticles (CUR-NP have recently been suggested to improve CUR bioavailability, but this has not been fully verified. Specifically, no data are available about curcumin glucuronide (CURG, the major metabolite of CUR found in the plasma following oral administration of CUR-NP. Herein, we investigated the absorption and metabolism of CUR-NP and evaluated whether CUR-NP improves CUR bioavailability.Methods: Following oral administration of CUR-NP in rats, we analyzed the plasma and organ distribution of CUR and its metabolites using high-performance liquid chromatography-tandem mass spectrometry. To elucidate the mechanism of increased intestinal absorption of CUR-NP, we prepared mixed micelles comprised of phosphatidylcholine and bile salts and examined the micellar solubility of CUR-NP. Additionally, we investigated the cellular incorporation of the resultant micelles into differentiated Caco-2 human intestinal cells.Results: Following in vivo administration of CUR-NP, CUR was effectively absorbed and present mainly as CURG in the plasma which contained significant amounts of the metabolite compared with

  8. Spherical Nucleic Acids as Intracellular Agents for Nucleic Acid Based Therapeutics

    Hao, Liangliang

    Recent functional discoveries on the noncoding sequences of human genome and transcriptome could lead to revolutionary treatment modalities because the noncoding RNAs (ncRNAs) can be applied as therapeutic agents to manipulate disease-causing genes. To date few nucleic acid-based therapeutics have been translated into the clinic due to challenges in the delivery of the oligonucleotide agents in an effective, cell specific, and non-toxic fashion. Unmodified oligonucleotide agents are destroyed rapidly in biological fluids by enzymatic degradation and have difficulty crossing the plasma membrane without the aid of transfection reagents, which often cause inflammatory, cytotoxic, or immunogenic side effects. Spherical nucleic acids (SNAs), nanoparticles consisting of densely organized and highly oriented oligonucleotides, pose one possible solution to circumventing these problems in both the antisense and RNA interference (RNAi) pathways. The unique three dimensional architecture of SNAs protects the bioactive oligonucleotides from unspecific degradation during delivery and supports their targeting of class A scavenger receptors and endocytosis via a lipid-raft-dependent, caveolae-mediated pathway. Owing to their unique structure, SNAs are able to cross cell membranes and regulate target genes expression as a single entity, without triggering the cellular innate immune response. Herein, my thesis has focused on understanding the interactions between SNAs and cellular components and developing SNA-based nanostructures to improve therapeutic capabilities. Specifically, I developed a novel SNA-based, nanoscale agent for delivery of therapeutic oligonucleotides to manipulate microRNAs (miRNAs), the endogenous post-transcriptional gene regulators. I investigated the role of SNAs involving miRNAs in anti-cancer or anti-inflammation responses in cells and in in vivo murine disease models via systemic injection. Furthermore, I explored using different strategies to construct

  9. Metabolic fate of poly-(lactic-co-glycolic acid)-based curcumin nanoparticles following oral administration

    Harigae, Takahiro; Nakagawa, Kiyotaka; Miyazawa, Taiki; Inoue, Nao; Kimura, Fumiko; Ikeda, Ikuo; Miyazawa, Teruo

    2016-01-01

    Purpose Curcumin (CUR), the main polyphenol in turmeric, is poorly absorbed and rapidly metabolized following oral administration, which severely curtails its bioavailability. Poly-(lactic-co-glycolic acid)-based CUR nanoparticles (CUR-NP) have recently been suggested to improve CUR bioavailability, but this has not been fully verified. Specifically, no data are available about curcumin glucuronide (CURG), the major metabolite of CUR found in the plasma following oral administration of CUR-NP. Herein, we investigated the absorption and metabolism of CUR-NP and evaluated whether CUR-NP improves CUR bioavailability. Methods Following oral administration of CUR-NP in rats, we analyzed the plasma and organ distribution of CUR and its metabolites using high-performance liquid chromatography-tandem mass spectrometry. To elucidate the mechanism of increased intestinal absorption of CUR-NP, we prepared mixed micelles comprised of phosphatidylcholine and bile salts and examined the micellar solubility of CUR-NP. Additionally, we investigated the cellular incorporation of the resultant micelles into differentiated Caco-2 human intestinal cells. Results Following in vivo administration of CUR-NP, CUR was effectively absorbed and present mainly as CURG in the plasma which contained significant amounts of the metabolite compared with other organs. Thus, CUR-NP increased intestinal absorption of CUR rather than decreasing metabolic degradation and conversion to other metabolites. In vitro, CUR encapsulated in CUR-NP was solubilized in mixed micelles; however, whether the micelles contained CUR or CUR-NP had little influence on cellular uptake efficiency. Therefore, we suggest that the high solubilization capacity of CUR-NP in mixed micelles, rather than cellular uptake efficiency, explains the high intestinal absorption of CUR-NP in vivo. Conclusion These findings provide a better understanding of the bioavailability of CUR and CUR-NP following oral administration. To improve

  10. Correlation of acid-base properties of substituted polystyrene-azo-pyrocatechol and characteristics of their chelates with zirconium

    Acid-base and complexing properties of new synthesized polymeric chelate-forming sorbents (PCS) - substituents of polystyrene-azo-pyrocatechol - are investigated and quantitative correlations between pKOH of functional analytical group (FAG) of sorbent and Hammet constants for para-substituent and ΔpKOH-ΔpK50 correlations of zirconium chelate-forming and pKOH-lgKstb (Kstb - constant of stability of PCS complexes with zirconium) of polychelates to study regularities of effect of peculiarities of structure and acid-base properties of FAG on parameters of zirconium chemical sorption. Established correlations make it possible to predict quantitative physicochemical parameters of sorbents and zirconium chemisorption process with the aim of directed synthesis and application of PCS in concentrating processes

  11. Acid-base properties and chemical composition of the surface of the InSb-ZnTe system

    The acid-base properties and chemical composition of the surface of solid solutions and binary components of the InSb-ZnTe system were studied by the hydrolytic adsorption, nonaqueous conductometric titration, mechanochemistry, IR spectroscopy, and mass spectrometry methods. The strength, nature, and concentration of acid centers were determined. Changes in the concentration of acid centers caused by surface exposure to CO and changes in the composition of the system were also studied. The mechanism of acid-base interactions was established. The chemical composition of the surface of system components exposed to air included adsorbed H2O molecules, OH- groups, hydrocarbon and oxo carbon compounds, and the products of surface atom oxidation. After thermal treatment in a vacuum, the composition of the surface approached the stoichiometric composition

  12. Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands.

    Valente, Luis M; Phillimore, Albert B; Etienne, Rampal S

    2015-08-01

    Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galápagos, this idea remains untested. Here, we reconstruct the temporal accumulation of terrestrial bird species of the Galápagos using a novel phylogenetic method that estimates rates of biota assembly for an entire community. We show that species richness on the archipelago is in an ascending phase and does not tend towards equilibrium. The majority of the avifauna diversifies at a slow rate, without detectable ecological limits. However, Darwin's finches form an exception: they rapidly reach a carrying capacity and subsequently follow a coalescent-like diversification process. Together, these results suggest that avian diversity of remote islands is rising, and challenge the mutual exclusivity of the non-equilibrium and equilibrium ecological paradigms. PMID:26105791

  13. A clinical study to assess the effectiveness of a hyaluronic acid-based procedure for treatment of premature ejaculation

    Littara, A; Palmieri, B.; Rottigni, V; Iannitti, T

    2013-01-01

    Premature ejaculation is a sexual debilitating condition affecting a large number of men worldwide and leading to important dysfunctions influencing the patients' affective and emotional life. Hyaluronic acid is a natural and safe compound that has been widely used not only in the aesthetic medicine clinic, but also for treatment of osteoarthritis. The present study shows the effectiveness of a hyaluronic acid-based procedure for treatment of premature ejaculation. A hundred and ten male pati...

  14. Mechanical Behavior and Thermal Stability of Acid-Base Phosphate Cements and Composites Fabricated at Ambient Temperature

    Colorado, Henry A.

    2013-01-01

    This dissertation presents the study of the mechanical behavior and thermal stability of acid-base phosphate cements (PCs) and composites fabricated at ambient temperature. These materials are also known as chemically bonded phosphate ceramics (CBPCs). Among other advantages of using PCs when compared with traditional cements are the better mechanical properties (compressive and flexural strength), lower density, ultra-fast (controllable) setting time, controllable pH, and an environmentally ...

  15. Acid-base and copper-binding properties of three organic matter fractions isolated from a forest floor soil solution

    van Schaik, Joris W. J.; Kleja, Dan B.; Gustafsson, Jon Petter

    2010-01-01

    Vast amounts of knowledge about the proton- and metal-binding properties of dissolved organic matter (DOM) in natural waters have been obtained in studies on isolated humic and fulvic (hydrophobic) acids. Although macromolecular hydrophilic acids normally make up about one-third of DOM, their proton- and metal-binding properties are poorly known. Here, we investigated the acid-base and Cu-binding properties of the hydrophobic (fulvic) acid fraction and two hydrophilic fractions isolated from ...

  16. A different point of view: a continuous tracing of acid-base titration with fiber-optic sensor

    YALTKAYA, Şerafettin; KENDİR, Esra

    2013-01-01

    Our main aim was to investigate variations in the refractive index of a solution during chemical reaction. The variation of refractive index was measured through the entire acid--base titration process, especially near the equivalence point. To determine the equivalence point, the conductivity of the solution and the refractive index were measured simultaneously. In this preliminary study, sodium hydroxide and hydrochloric acid were used as the base and the acid solution, respective...

  17. Effect of intercalation of (HBO2)n and mechanochemical treatment on acid-base properties of kaolinite

    The effect of intercalation of (HBO2)n in kaolinite and mechanochemical treatment of mixtures of mineral with H3BO3 on acid-base properties of kaolinite surface was studied by potentiometric titration. It was found that intercalation of the mineral as well as mechanochemical treatment of the mixture depressed the acidity of the kaolinite surface, specifically at their combined effect. 8 refs., 1 fig., 1 tab

  18. Mixed acid-base disorders, hydroelectrolyte imbalance and lactate production in hypercapnic respiratory failure: the role of noninvasive ventilation.

    Claudio Terzano

    Full Text Available BACKGROUND: Hypercapnic Chronic Obstructive Pulmonary Disease (COPD exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV when treating hypercapnic respiratory failure. METHODS: Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO(2 and PaCO(2 and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV. RESULTS: Nine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7% mixed respiratory acidosis-metabolic alkalosis, 10/36 (27.8% respiratory acidosis and 3/5 (60% mixed respiratory-metabolic acidosis patients (p = 0.026, with durations of 45.1 ± 9.8, 36.2 ± 8.9 and 53.3 ± 4.1 hours, respectively (p = 0.016. The duration of ventilation was associated with higher blood lactate (p<0.001, lower pH (p = 0.016, lower serum sodium (p = 0.014 and lower chloride (p = 0.038. Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis-metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder. CONCLUSIONS: Mixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated.

  19. Investigation of thermal and viscoelastic properties of polymers relevant to hot melt extrusion - III: Polymethacrylates and polymethacrylic acid based polymers.

    Tapan Parikh; Simerdeep Singh Gupta; Anuprabha Meena; Serajuddin, Abu T. M.

    2014-01-01

    Polymers are a major part of final medicinal drug products prepared by hot melt extrusion (HME). Therefore it is necessary to understand their behavior when subjected to heat and mechanical stresses during the development of the HME processes. The aim of this work was to generate a database of the physicochemical properties for polymethacrylates and polymethacrylic acid based polymers relevant to HME. All six polymers tested were amorphous and had < 2% moisture. In differential scanning calo...

  20. Recent developments in nucleic acid based techniques for use in rumen manipulation

    Christopher McSweeney

    2009-07-01

    Full Text Available Nucleic acid-based techniques which can be used to characterise complex microbial communities without incubation are now being employed regularly in ruminant nutrition studies. Conventional culture-based methods for enumerating rumen microorganisms (bacteria, archaea, protozoa, and fungi have been superseded and are now used mainly to obtain pure isolates of novel organisms and reference strains that are required for the development and validation of the nucleic acid approaches. These reference strains are also essential for physiological studies of the lifestyle of the organisms as well as sources of genomic DNA and RNA that can be analysed for functional gene activity. The foundation of the molecular ecology techniques is 16S/18S rDNA sequence analysis which has provided a phylogenetically based classification scheme for enumeration and identification of microbial community members. The use of this marker gene in assays involving the use of single nucleic acid probes or primer sets is rapidly evolving to high throughput approaches such as microarray analysis and new generation sequencing technologies. While these analyses are very informative for determining the composition of the microbial community and monitoring changes in population size, they can only infer function based on these observations. The focus of nucleic acid research is now shifting to the functional analysis of the ecosystem which involves the measurement of functional genes and their expression in the predominant or specific members of the rumen microbial community. Functional gene studies are less developed than 16S rDNA-based analysis of community structure. Also for gene expression studies there are inherent problems involved in extracting high quality RNA from digesta, and priming cDNA synthesis from bacterial mRNA. This paper reviews nucleic acid based molecular methods which have recently been developed for studying the structure and function of rumen microbial

  1. Gallic acid-based indanone derivative interacts synergistically with tetracycline by inhibiting efflux pump in multidrug resistant E. coli.

    Dwivedi, Gaurav Raj; Tiwari, Nimisha; Singh, Aastha; Kumar, Akhil; Roy, Sudeep; Negi, Arvind Singh; Pal, Anirban; Chanda, Debabrata; Sharma, Ashok; Darokar, Mahendra P

    2016-03-01

    The purpose of the present study was to study the synergy potential of gallic acid-based derivatives in combination with conventional antibiotics using multidrug resistant cultures of Escherichia coli. Gallic acid-based derivatives significantly reduced the MIC of tetracycline against multidrug resistant clinical isolate of E. coli. The best representative, 3-(3',4,'5'-trimethoxyphenyl)-4,5,6-trimethoxyindanone-1, an indanone derivative of gallic acid, was observed to inhibit ethidium bromide efflux and ATPase which was also supported by in silico docking. This derivative extended the post-antibiotic effect and decreased the mutation prevention concentration of tetracycline. This derivative in combination with TET was able to reduce the concentration of TNFα up to 18-fold in Swiss albino mice. This derivative was nontoxic and well tolerated up to 300 mg/kg dose in subacute oral toxicity study in mice. This is the first report of gallic acid-based indanone derivative as drug resistance reversal agent acting through ATP-dependent efflux pump inhibition. PMID:26658982

  2. Non-equilibrium chemistry in space

    Chemical processes by accelerated species do not proceed in thermal equilibrium with the target molecules. The hot or suprathermal reactions are characterized by the fact that a kinetic energy ranging from about 1 to few 10 eV is imparted to the collision complex. Reaction rates are by orders of magnitude higher and products are more diversified than in classic thermally controlled reactions. Space is rich in energetic atoms, ions, molecules, fragments, clusters, and grains from cosmic rays, solar or stellar radiation, shock waves and many secondary acceleration processes with energies ranging from a few eV (photodissociation) to some TeV (cosmic rays). Non-equilibrium chemistry is, thus, typical for space. Suprathermal reactions in the solid state can effectively compete with radiolysis or photolysis and ion molecule interactions, particularly in view of the formation of complex organic matter by multicenter reactions in the collision cascades. (orig.)

  3. Equilibrium and stability of a rotating plasma

    The author considers the equilibrium and stability of a rotating plasma. The kinetic equations for ions and electrons supplemented with the Maxwell equations and the appropriate boundary conditions are used. Two different models for the rotating plasma are considered: the equilibrium of a 'fast' rotating plasma (Magneto Hydrodynamic ordering) and the stability of a slowly rotating, 'weakly' unstable plasma (Finite Larmor Radius ordering). A striking difference between these orderings is the fact that, regarding the stability of the plasma, for a F.L.R. plasma viscosity effects due to the finite Larmor radius are important, whereas in a M.H.D. plasma they are negligible (at least to the required order). (Auth.)

  4. An equilibrium approach to modelling social interaction

    Gallo, Ignacio

    2009-01-01

    The aim of this work is to put forward a statistical mechanics theory of social interaction, generalizing econometric discrete choice models. After showing the formal equivalence linking econometric multinomial logit models to equilibrium statical mechanics, a multi-population generalization of the Curie-Weiss model for ferromagnets is considered as a starting point in developing a model capable of describing sudden shifts in aggregate human behaviour. Existence of the thermodynamic limit for the model is shown by an asymptotic sub-additivity method and factorization of correlation functions is proved almost everywhere. The exact solution of the model is provided in the thermodynamical limit by finding converging upper and lower bounds for the system's pressure, and the solution is used to prove an analytic result regarding the number of possible equilibrium states of a two-population system. The work stresses the importance of linking regimes predicted by the model to real phenomena, and to this end it propo...

  5. Punctuated equilibrium in a neontological context.

    Monroe, Melanie J; Bokma, Folmer

    2010-09-01

    The theory of punctuated equilibrium, which proposes that biological species evolve rapidly when they originate rather than gradually over time, has sparked intense debate between palaeontologists and evolutionary biologists about the mode of character evolution and the importance of natural selection. Difficulty in interpreting the fossil record prevented consensus, and it remains disputed as to what extent gradual change in established species is responsible for phenotypic differences between species. Against the historical background of the concept of evolution concentrated in speciation events, we review attempts to investigate tempo and mode of evolution using present-day species since the introduction of the theory of punctuated equilibrium in 1972. We discuss advantages, disadvantages, and prospects of using neontological data, methodological advances, and the findings of some recent studies. PMID:20514523

  6. Line radiative transfer and statistical equilibrium*

    Kamp Inga

    2015-01-01

    Full Text Available Atomic and molecular line emission from protoplanetary disks contains key information of their detailed physical and chemical structures. To unravel those structures, we need to understand line radiative transfer in dusty media and the statistical equilibrium, especially of molecules. I describe here the basic principles of statistical equilibrium and illustrate them through the two-level atom. In a second part, the fundamentals of line radiative transfer are introduced along with the various broadening mechanisms. I explain general solution methods with their drawbacks and also specific difficulties encountered in solving the line radiative transfer equation in disks (e.g. velocity gradients. I am closing with a few special cases of line emission from disks: Radiative pumping, masers and resonance scattering.

  7. Equilibrium fluctuation theorems compatible with anomalous response

    Velazquez, L.; Curilef, S.

    2010-12-01

    Previously, we have derived a generalization of the canonical fluctuation relation between heat capacity and energy fluctuations C = β2langδU2rang, which is able to describe the existence of macrostates with negative heat capacities C < 0. In this work, we extend our previous results for an equilibrium situation with several control parameters to account for the existence of states with anomalous values in other response functions. Our analysis leads to the derivation of three different equilibrium fluctuation theorems: the fundamental and the complementary fluctuation theorems, which represent the generalization of two fluctuation identities already obtained in previous works, and the associated fluctuation theorem, a result that has no counterpart in the framework of Boltzmann-Gibbs distributions. These results are applied to study the anomalous susceptibility of a ferromagnetic system, in particular, the case of the 2D Ising model.

  8. Equilibrium time correlation functions in open systems

    Zhu, Jinglong; Agarwal, Animesh; Site, Luigi Delle

    2014-01-01

    We study equilibrium time correlation functions for liquid water at room temperature employing the Molecular Dynamics (MD) adaptive resolution method AdResS in its Grand Canonical formulation (GC-AdResS). This study introduces two technical innovations: the employment of a local thermostat that acts only in the reservoir and the consequent construction of an "ideal" Grand Canonical reservoir of particles and energy. As a consequence the artificial action of a thermostat in the calculation of equilibrium time correlation functions of standard NVT simulations is efficiently removed. The success of the technical innovation provides the basis for formulating a profound conceptual problem, that is the extension of Liouville theorem to open systems (Grand Canonical ensemble), a question, so far, treated neither in MD nor (in general) in statistical physics.

  9. Uncertainty Principle Consequences at Thermal Equilibrium

    Pachon, Leonardo A; Zueco, David; Brumer, Paul

    2014-01-01

    Contrary to the conventional wisdom that deviations from standard thermodynamics originate from the strong coupling to the bath, it is shown that these deviations are intimately linked to the power spectrum of the thermal bath. Specifically, it is shown that the lower bound of the dispersion of the total energy of the system, imposed by the uncertainty principle, is dominated by the bath power spectrum and therefore, quantum mechanics inhibits the system thermal-equilibrium-state from being described by the canonical Boltzmann's distribution. This is in sharp contrast to the classical case, for which the thermal equilibrium distribution of a system interacting via central forces with pairwise-self-interacting environment, irrespective of the interaction strength, is shown to be \\emph{exactly} characterized by the canonical Boltzmann distribution. As a consequence of this analysis, we define an \\emph{effective coupling} to the environment that depends on all energy scales in the system and reservoir interactio...

  10. Equilibrium and stability of helical systems

    For the purpose of preparing basic data for designing a new large helical system, we have made a numerical survey of equilibrium and linear stabilities of l = 2 torsatron/heliotron. We try to find out optimum configuration in a wide parameter space where the coil aspect ratio γc is changed as well as the pitch period number M. We determine the parameter region within which a high β current-less plasma is obtained from the view points of both the equilibrium and stability limits. Moreover, we execute a sensitivity analysis of various parameters on the stability, such as the vertical field, the quadruple field, the pressure profile, the shape of the helical coil, and the pitch modulation. We find each parameter gives strong influence on the stability. (author)

  11. On equilibrium charge distribution above dielectric surface

    Yu.V. Slyusarenko

    2009-01-01

    Full Text Available The problem of the equilibrium state of the charged many-particle system above dielectric surface is formulated. We consider the case of the presence of the external attractive pressing field and the case of its absence. The equilibrium distributions of charges and the electric field, which is generated by these charges in the system in the case of ideally plane dielectric surface, are obtained. The solution of electrostatic equations of the system under consideration in case of small spatial heterogeneities caused by the dielectric surface, is also obtained. These spatial inhomogeneities can be caused both by the inhomogeneities of the surface and by the inhomogeneous charge distribution upon it. In particular, the case of the "wavy" spatially periodic surface is considered taking into account the possible presence of the surface charges.

  12. Uniqueness of Nash equilibrium in vaccination games.

    Bai, Fan

    2016-12-01

    One crucial condition for the uniqueness of Nash equilibrium set in vaccination games is that the attack ratio monotonically decreases as the vaccine coverage level increasing. We consider several deterministic vaccination models in homogeneous mixing population and in heterogeneous mixing population. Based on the final size relations obtained from the deterministic epidemic models, we prove that the attack ratios can be expressed in terms of the vaccine coverage levels, and also prove that the attack ratios are decreasing functions of vaccine coverage levels. Some thresholds are presented, which depend on the vaccine efficacy. It is proved that for vaccination games in homogeneous mixing population, there is a unique Nash equilibrium for each game. PMID:27465224

  13. Adaptive resolution simulation in equilibrium and beyond

    Wang, H.; Agarwal, A.

    2015-09-01

    In this paper, we investigate the equilibrium statistical properties of both the force and potential interpolations of adaptive resolution simulation (AdResS) under the theoretical framework of grand-canonical like AdResS (GC-AdResS). The thermodynamic relations between the higher and lower resolutions are derived by considering the absence of fundamental conservation laws in mechanics for both branches of AdResS. In order to investigate the applicability of AdResS method in studying the properties beyond the equilibrium, we demonstrate the accuracy of AdResS in computing the dynamical properties in two numerical examples: The velocity auto-correlation of pure water and the conformational relaxation of alanine dipeptide dissolved in water. Theoretical and technical open questions of the AdResS method are discussed in the end of the paper.

  14. Equilibrium policies when preferences are time inconsistent

    Ekeland, Ivar

    2008-01-01

    This paper characterizes differentiable and subgame Markov perfect equilibria in a continuous time intertemporal decision problem with non-constant discounting. Capturing the idea of non commitment by letting the commitment period being infinitesimally small, we characterize the equilibrium strategies by a value function, which must satisfy a certain equation. The equilibrium equation is reminiscent of the classical Hamilton-Jacobi-Bellman equation of optimal control, but with a non-local term leading to differences in qualitative behavior. As an application, we formulate an overlapping generations Ramsey model where the government maximizes a utilitarian welfare function defined as the discounted sum of successive generations' lifetime utilities. When the social discount rate is different from the private discount rate, the optimal command allocation is time inconsistent and we retain subgame perfection as a principle of intergenerational equity. Existence of multiple subgame perfect equilibria is establishe...

  15. Equilibrium Macroscopic Structure Revisited from Spatial Constraint

    Yuge, Koretaka

    2016-02-01

    In classical systems, we reexamine how macroscopic structures in equilibrium state connect with spatial constraint on the systems. For example, volume and density as the constraint for liquids in rigid box, and crystal lattice as the constraint for crystalline solids. We find that in disordered states, equilibrium macroscopic structure, depending on temperature and on multibody interactions in the system, can be well characterized by a single special microscopic structure independent of temperature and of interactions. The special microscopic structure depends only on the spatial constraint. We demonstrate the present findings providing (i) significantly efficient and systematic prediction of macroscopic structures for possible combination of constituents in multicomponent systems using first-principles calculations, and (ii) unique and accurate prediction of multibody interactions in given system from measured macroscopic structure, without performing trial-and-error simulation.

  16. Fluctuations in Hertz chains at equilibrium

    Przedborski, Michelle; Harroun, Thad A

    2016-01-01

    We examine the long-term behaviour of non-integrable, energy-conserved, 1D systems of macroscopic grains interacting via a contact-only generalized Hertz potential and held between stationary walls. Existing dynamical studies showed the absence of energy equipartitioning in such systems, hence their long-term dynamics was described as quasi-equilibrium. Here we show that, if spatial symmetry is broken, these systems do in fact reach thermal equilibrium as time $t \\to \\infty$, as indicated by the calculated heat capacity. As a byproduct, we show how fluctuations of system quantities, and thus the distribution functions, are influenced by the Hertz potential. In particular, the variance of the system's kinetic energy probability density function is reduced by a factor related to the contact potential.

  17. A Punctuated Equilibrium in French Budgeting Processes

    B. Baumgartner, Frank; Foucault, Martial; François, Abel

    2006-01-01

    We use data on French budgeting to test models of friction, incrementalism and punctuated equilibrium. Data include the overall state budget since 1820; ministerial budgets for seven ministries since 1868; and a more complete ministerial series covering ten ministries since 1947. Our results in every case are remarkably similar to the highly leptokurtic distributions that Jones and Baumgartner (2005) demonstrated in US budgeting processes. This suggests that general characteristics of adminis...

  18. A Central Limit Theorem for Punctuated Equilibrium

    Bartoszek, Krzysztof

    2016-01-01

    Current evolutionary biology models usually assume that a phenotype undergoes gradual change. This is in stark contrast to biological intuition, which indicates that change can also be punctuated - the phenotype can jump. Such a jump can especially occur at speciation, i.e. dramatic change occurs that drives the species apart. Here we derive a central limit theorem for punctuated equilibrium. We show that, if adaptation is fast, for weak convergence to hold, dramatic change has to be a rare e...

  19. Computing Cournot Equilibrium through Maximization over Prices

    Orbay, Hakan

    2007-01-01

    This paper presents an alternative characterization of internal Cournot equilibrium based on the first-order conditions corresponding to profit maximization over prices. This characterization is particularly useful when the market is described in terms of demand functions (rather than inverse-demand functions). A significant computational advantage is gained in homogeneous good cases as demand functions need not be inverted and simple first order conditions are obtained. ...

  20. Vapour liquid equilibrium measurements for process design

    Uusi-Kyyny, Petri

    2004-01-01

    In recent years it has become increasingly important to develop new oxygenate and isooctane technologies and processes that meet the continuously stricter environmental requirements. Some of the new process schemes use renewable raw materials in order to meet the European Union biofuel requirements. One of the most important requirements for the design of such separation processes includes the knowledge of vapour liquid equilibrium (VLE) behaviour. There are methods to estimate VLE but for th...

  1. A Cubic Micron of Equilibrium Pair Plasma?

    Katz, J. I.

    1998-01-01

    Is it possible to create a small volume of equilibrium pair plasma in the laboratory with an intense laser pulse? No. The required power would exceed 10^{18} W. The number of seed particles required to absorb the laser energy would approach the number of pairs in the desired plasma, and their radiation in a visible laser field would occur at extremely high frequencies.

  2. Modeling Growing Economies in Equilibrium and Disequilibrium

    Kelley, A C; W.C. Sanderson; Williamson, J. G.

    1983-01-01

    The papers in this volume were presented and discussed at a meeting held at IIASA. The meeting's goals were to stimulate interaction and collaboration, and to encourage setting research priorities for the future. Indeed, it is in this latter area where the meeting appeared to yield some of its greatest benefits. It became clear from the deliberations that much needs to be done to better specify the microfoundations of general equilibrium models. More realistic specifications of "conflict...

  3. Equilibrium Asset Prices Under Imperfect Corporate Control

    James Dow; Gary Gorton; Arvind Krishnamurthy

    2003-01-01

    Shareholders have imperfect ontrol over the decisions of the management of a firm. We integrate a widely accepted version of the separation of ownership and control -- Jensen's (1986) free cash flow theory--into a dynamic equilibrium model and study the effect of imperfect corporate control on asset prices and investment. We assume that firms are run by empire-building managers who prefer to invest all free cash flow rather than distributing it to shareholders. Sharefholders are aware of this...

  4. Factor Markets in General Computable Equilibrium Models

    Banse, Martin; Shutes, Lindsay; Dixon, Peter; van Meijl, Hans; Rimmer, Maureen; Tabeau, Andrzej; Geert WOLTJER; Rothe, Andrea

    2013-01-01

    One objective of Computable general equilibrium (CGE) models is the analysis of economy-wide effects of policy measures. The focus of the Factor Markets project is to analyse the functioning of factor markets for agriculture in the EU-27, including the Candidate Countries. While agricultural and food markets are fully integrated in a European single market, subject to an EU-wide common policy, the Common Agricultural Policy (CAP), this is not the case for the agricultural factor markets capit...

  5. Data issues in general equilibrium modelling

    Beutre, Benjamin; Rodriguez, Gil; Hom M. Pant

    2003-01-01

    In recent years global general equilibrium (GE) models have been used to analyse policy issues such as trade liberalisation, regional integration and environmental policies. While a global CGE model is an excellent tool to perform a comprehensive analysis of such policies, it requires an enormous amount of data to calibrate or parameterise the model itself. Quality differences in the data sets might affect the results of the model simulation. Identifying and removing problems in the database ...

  6. Non-equilibrium thermodynamics of gravitational screens

    Freidel, Laurent; Yokokura, Yuki

    2014-01-01

    We study the Einstein gravity equations projected on a timelike surface, which represents the time evolution of what we call a gravitational screen. We show that such a screen behaves like a viscous bubble with a surface tension and an internal energy, and that the Einstein equations take the same forms as non-equilibrium thermodynamic equations for a viscous bubble. We provide a consistent dictionary between gravitational and thermodynamical variables. In the non-viscous cases there are thre...

  7. Equilibrium analysis, banking, contagion and financial fragility

    Tsomocos, Dimitrios P.

    2003-01-01

    This paper contains a General Equilibrium model of an economy with Incomplete Markets (GEI) with money and default. The model is a simplified version of the real world consisting of a non-bank private sector, banks, a Central Bank, a government and a regulator. The model is used to analyse actions by policy makers and to identify policy relevant empirical work. Key analytical results are: A financially fragile system need not collapse; efficiency can be improved with policy intervention; and ...

  8. The general equilibrium theory as economic metatheory

    MAURICIO MARTINELLI LUPERI

    2015-01-01

    Many economists show certain nonconformity relative to the excessive mathematical formalization of economics. This stems from dissatisfaction with the old debate about the lack of correspondence between mainstream theoretical models and reality. Although we do not propose to settle this debate here, this article seeks to associate the mismatch of mathematized models with the reality of the adoption of the hypothetical-deductive method as reproduced by general equilibrium. We begin by defining...

  9. Bifurcated Helical Core Equilibrium States in Tokamaks

    Full text: Tokamaks with weak to moderate reversed central magnetic shear in which the minimum of the inverse rotational transform qmin is in the neighbourhood of unity can trigger bifurcated MagnetoHydroDynamic (MHD) equilibrium states. In addition to the standard axisymmetric branch that can be obtained with standard Grad-Shafranov solvers, a novel branch with a three-dimensional (3D) helical core has been computed with the ANIMEC code, an anisotropic pressure extension of the VMEC code. The solutions have imposed nested magnetic flux surfaces and are similar to saturated ideal internal kink modes. The difference in energy between both possible branches is very small. Plasma elongation, current and β enhance the susceptibility for bifurcations to occur. An initial value nonlinear ideal MHD evolution of the axisymmetric branch compares favourably with the helical core equilibrium structures calculated. Peaked prescribed pressure profiles reproduce the 'snake' structures observed in many tokamaks which has led to a new explanation of the snake as a bifurcated helical equilibrium state that results from a saturated ideal internal kink in which pellets or impurities induce a hollow current profile. Snake equilibrium structures are computed in free boundary TCV tokamak simulations. Magnetic field ripple and resonant magnetic perturbations in MAST free boundary calculations do not alter the helical core deformation in a significant manner when qmin is near unity. These bifurcated solutions constitute a paradigm shift that motivates the application of tools developed for stellarator research in tokamak physics investigations. The examination of fast ion confinement in this class of equilibria is performed with the VENUS code in which a coordinate independent noncanonical phase-space Lagrangian formulation of guiding centre drift orbit theory has been implemented. (author)

  10. Equilibrium Gold Nanoclusters Quenched with Biodegradable Polymers

    Murthy, Avinash K.; Stover, Robert J.; Borwankar, Ameya U.; Nie, Golay D.; Gourisankar, Sai; Truskett, Thomas M.; Konstantin V. Sokolov; Johnston, Keith P.

    2012-01-01

    Although sub-100 nm nanoclusters of metal nanoparticles are of interest in many fields including biomedical imaging, sensors and catalysis, it has been challenging to control their morphologies and chemical properties. Herein, a new concept is presented to assemble equilibrium Au nanoclusters of controlled size by tuning the colloidal interactions with a polymeric stabilizer, PLA(1k)-b-PEG(10k)-b-PLA(1k). The nanoclusters form upon mixing a dispersion of ~5 nm Au nanospheres with a polymer so...

  11. Regret Theory and Equilibrium Asset Prices

    Jiliang Sheng; Jian Wang; Jun Yang

    2014-01-01

    Regret theory is a behavioral approach to decision making under uncertainty. In this paper we assume that there are two representative investors in a frictionless market, a representative active investor who selects his optimal portfolio based on regret theory and a representative passive investor who invests only in the benchmark portfolio. In a partial equilibrium setting, the objective of the representative active investor is modeled as minimization of the regret about final wealth relativ...

  12. Nanostructured energy devices equilibrium concepts and kinetics

    Bisquert, Juan

    2014-01-01

    Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu

  13. A strictly hyperbolic equilibrium phase transition model

    Allaire, G [Ecole Polytech, CNRS, CMAP, F-91128 Palaiseau (France); Faccanoni, G; Kokh, S. [CEA Saclay, DEN, DANS, DM2S, F-91191 Gif Sur Yvette, (France)

    2007-01-15

    This Note is concerned with the strict hyperbolicity of the compressible Euler equations equipped with an equation of state that describes the thermodynamical equilibrium between the liquid phase and the vapor phase of a fluid. The proof is valid for a very wide class of fluids. The argument only relies on smoothness assumptions and on the classical thermodynamical stability assumptions, that requires a definite negative Hessian matrix for each phase entropy as a function of the specific volume and internal energy. (authors)

  14. Immigration and Outsourcing: A General Equilibrium Analysis

    Subhayu Bandoyopadhyay; Wall, Howard J.

    2005-01-01

    This paper analyzes the issues of immigration and outsourcing in a general-equilibrium model of international factor mobility. In our model, legal immigration is controlled through a quota, while outsourcing is determined both by the firms (in response to market conditions) and through policy-imposed barriers. A loosening of the immigration quota reduces outsourcing, enriches capitalists, leads to losses for native workers, and raises national income. If the nation targets an exogenously dete...

  15. Three terminal non-equilibrium superconducting devices

    I review various non-equilibrium three terminal superconducting devices. The Quiteron, while initially promising, has major failings that make it uncompetitive as a high speed three terminal device. By examining alternatives to the Quiteron structure we come to the conclusion that a quasiparticle injected microstrip device somewhat similar in concept to the original CLINK device of Wong et al. has considerable promise, provided that a low carrier density superconductor is employed as the microstrip material. (orig./BUD)

  16. Asset Market Equilibrium with Short-Selling.

    Nielsen, Lars Tyge

    1989-01-01

    This paper presents simple conditions and a simple proof of the existence of equilibrium in asset markets where short-selling is allowed and satiation is possible. Unlike standard nonsatiation assumptions, the one used here is weak enough to be reasonable in the mean-variance capital asset pricing model and in asset market models where investors maximize expected utility and where total returns to individual assets may be negative. Copyright 1989 by The Review of Economic Studies Limited.

  17. On the Equilibrium of Simplicial Masonry Structures

    de Goes, Fernando; Alliez, Pierre; Owhadi, Houman; Desbrun, Mathieu

    2013-01-01

    We present a novel approach for the analysis and design of selfsupporting simplicial masonry structures. A finite-dimensional formulation of their compressive stress field is derived, offering a new interpretation of thrust networks through numerical homogenization theory. We further leverage geometric properties of the resulting force diagram to identify a set of reduced coordinates characterizing the equilibrium of simplicial masonry. We finally derive computational form-finding tools that ...

  18. Uniform convergence to equilibrium for granular media

    Bolley, François; Guillin, Arnaud

    2012-01-01

    We study the long time asymptotics of a nonlinear, nonlocal equation used in the modelling of granular media. We prove a uniform exponential convergence to equilibrium for degenerately convex and non convex interaction or confinement potentials, improving in particular results by J. A. Carrillo, R. J. McCann and C. Villani. The method is based on studying the dissipation of the Wasserstein distance between a solution and the steady state.

  19. Input and output inventories in general equilibrium

    Iacoviello, Matteo; SCHIANTARELLI, FABIO; Schuh, Scott

    2007-01-01

    We build and estimate a two-sector (goods and services) dynamic stochastic general equilibrium model with two types of inventories: materials (input) inventories facilitate the production of finished goods, while finished goods (output) inventories yield utility services. The model is estimated using Bayesian methods. The estimated model replicates the volatility and cyclicality of inventory investment and inventory-to-target ratios. Although inventories are an important element of the model'...

  20. The mathematical description of equilibrium bipedal locomotion

    Ткач, Михайло Мартинович

    2012-01-01

     This paper analyzes the current state of the construction of anthropomorphic walking machines. The areas of their future implementation. The basis of the publication is to define the criteria for compliance with the unstable equilibrium of walking aids by anthropic simulation. In particular, it provides a formalized solution to strike a balance on the surfaces of the second kind on the basis of observations of the center of mass displacement of the projection apparatus on the specified surfa...

  1. Bertrand Equilibrium in a Differentiated Duopoly.

    1992-01-01

    This paper studies the stability of price competition in a horizontally differentiated duopoly. The firms' demand is derived from a distribution of consumer preferences. This description of the consumer sector is applicable to a large class of differentiated commodity markets, including spatial competition models. The author shows that there is a (pure) price-setting equilibrium when consumer tastes are sufficiently dispersed. Further conditions on the dispersedness of preferences guarantee u...

  2. 'Residual' Wage Disparity in Directed Search Equilibrium

    John Kennes; Ian Paul King; Benoit Julien

    2002-01-01

    We examine how much of the observed wage dispersion among similar workers can be explained as a consequence of a lack of coordination among employers. To do this, we construct a directed search model with homogenous workers but where firms can create either good or bad jobs, aimed at either employed or unemployed workers. Workers in our model can also sell their labor to the highest bidder. The stationary equilibrium has both technology dispersion \\226 different wages due to different job qua...

  3. The equilibrium size distribution of rouleaux.

    Perelson, A. S.; Wiegel, F.W.

    1982-01-01

    Rouleaux are formed by the aggregation of red blood cells in the presence of macromolecules that bridge the membranes of adherent erythrocytes. We compute the size and degree of branching of rouleaux for macroscopic systems in thermal equilibrium in the absence of fluid flow. Using techniques from statistical mechanics, analytical expressions are derived for (a) the average number of rouleaux consisting of n cells and having m branch points; (b) the average number of cells per rouleau; (c) th...

  4. Statistical approach to partial equilibrium analysis

    Wang, Yougui; Stanley, H. E.

    2009-04-01

    A statistical approach to market equilibrium and efficiency analysis is proposed in this paper. One factor that governs the exchange decisions of traders in a market, named willingness price, is highlighted and constitutes the whole theory. The supply and demand functions are formulated as the distributions of corresponding willing exchange over the willingness price. The laws of supply and demand can be derived directly from these distributions. The characteristics of excess demand function are analyzed and the necessary conditions for the existence and uniqueness of equilibrium point of the market are specified. The rationing rates of buyers and sellers are introduced to describe the ratio of realized exchange to willing exchange, and their dependence on the market price is studied in the cases of shortage and surplus. The realized market surplus, which is the criterion of market efficiency, can be written as a function of the distributions of willing exchange and the rationing rates. With this approach we can strictly prove that a market is efficient in the state of equilibrium.

  5. TEA: A Code Calculating Thermochemical Equilibrium Abundances

    Blecic, Jasmina; Harrington, Joseph; Bowman, M. Oliver

    2016-07-01

    We present an open-source Thermochemical Equilibrium Abundances (TEA) code that calculates the abundances of gaseous molecular species. The code is based on the methodology of White et al. and Eriksson. It applies Gibbs free-energy minimization using an iterative, Lagrangian optimization scheme. Given elemental abundances, TEA calculates molecular abundances for a particular temperature and pressure or a list of temperature–pressure pairs. We tested the code against the method of Burrows & Sharp, the free thermochemical equilibrium code Chemical Equilibrium with Applications (CEA), and the example given by Burrows & Sharp. Using their thermodynamic data, TEA reproduces their final abundances, but with higher precision. We also applied the TEA abundance calculations to models of several hot-Jupiter exoplanets, producing expected results. TEA is written in Python in a modular format. There is a start guide, a user manual, and a code document in addition to this theory paper. TEA is available under a reproducible-research, open-source license via https://github.com/dzesmin/TEA.

  6. Equilibrium gold nanoclusters quenched with biodegradable polymers.

    Murthy, Avinash K; Stover, Robert J; Borwankar, Ameya U; Nie, Golay D; Gourisankar, Sai; Truskett, Thomas M; Sokolov, Konstantin V; Johnston, Keith P

    2013-01-22

    Although sub-100 nm nanoclusters of metal nanoparticles are of interest in many fields including biomedical imaging, sensors, and catalysis, it has been challenging to control their morphologies and chemical properties. Herein, a new concept is presented to assemble equilibrium Au nanoclusters of controlled size by tuning the colloidal interactions with a polymeric stabilizer, PLA(1k)-b-PEG(10k)-b-PLA(1k). The nanoclusters form upon mixing a dispersion of ~5 nm Au nanospheres with a polymer solution followed by partial solvent evaporation. A weakly adsorbed polymer quenches the equilibrium nanocluster size and provides steric stabilization. Nanocluster size is tuned from ~20 to ~40 nm by experimentally varying the final Au nanoparticle concentration and the polymer/Au ratio, along with the charge on the initial Au nanoparticle surface. Upon biodegradation of the quencher, the nanoclusters reversibly and fully dissociate to individual ~5 nm primary particles. Equilibrium cluster size is predicted semiquantitatively with a free energy model that balances short-ranged depletion and van der Waals attractions with longer-ranged electrostatic repulsion, as a function of the Au and polymer concentrations. The close spacings of the Au nanoparticles in the clusters produce strong NIR extinction over a broad range of wavelengths from 650 to 900 nm, which is of practical interest in biomedical imaging. PMID:23230905

  7. Pre-equilibrium contribution in nuclear reactions

    The advent of variable energy cyclotrons in the recent past had made possible the study of excitation functions and particle spectra in the energy range 20-200 MeV. Certain new experimental features, emerging from these studies, have called for a new explanation, which the recently proposed pre-equilibrium models tend to offer in a sort of 'old wine in new bottles'. The basic concept that the nuclear reaction proceeds through a series of two-body scattering processes in the target nucleus-intranuclear cascades, is a concept borrowed from high energy interactions at Gev, where the de Broglie wave length of the incident particle is short compared to inter-nucleon spacing. But, how does the idea work at 100 MeV, where this condition is no longer valid. Other questions and ideological differences between some of the pre-equilibrium models are discussed. It is shown how the recently proposed unified model resolves the controversy between hybrid and exciton models concerning the use of single particle or exciton life times in the calculation. Typical experimental results on the excitation functions and particle spectra of some charged particle induced reactions are presented. The pre-equilibrium contribution in these reactions is compared with model predictions, highlighting the merits, demerits and future promise of the present theories. (auth.)

  8. Hamiltonian approach to the magnetostatic equilibrium problem

    The purpose of this paper is to investigate the classical scalar-pressure magnetostatic equilibrium problem for non-symmetric configurations in the framework of a Hamiltonian approach. Requiring that the equilibrium admits locally, in a suitable subdomain, a family of nested toroidal magnetic surfaces, the Hamiltonian equations describing the magnetic flux lines in such a subdomain are obtained for general curvilinear coordinate systems. The properties of such Hamiltonian system are investigated. A representation of the magnetic field in terms of arbitrary general curvilinear coordinates is thus obtained. Its basic feature is that the magnetic field must fulfill suitable periodicity constraints to be imposed on arbitrary rational magnetic surfaces for general non-symmetric toroidal equilibria, i.e., it is quasi-symmetric. Implications for the existence of magnetostatic equilibria are pointed out. In particular, it is proven that a generalized equilibrium equation exists for such quasi-symmetric equilibria, which extends the Grad-Shafranov equation to fully three-dimensional configurations. As an application, the case is considered of quasi-helical equilibria, i.e., displaying a magnetic field magnitude depending on the poloidal (χ) and toroidal (var-theta) angles only in terms of α=χ-Nθ with N an arbitrary integer

  9. Multi-period equilibrium/near-equilibrium in electricity markets based on locational marginal prices

    Garcia Bertrand, Raquel

    In this dissertation we propose an equilibrium procedure that coordinates the point of view of every market agent resulting in an equilibrium that simultaneously maximizes the independent objective of every market agent and satisfies network constraints. Therefore, the activities of the generating companies, consumers and an independent system operator are modeled: (1) The generating companies seek to maximize profits by specifying hourly step functions of productions and minimum selling prices, and bounds on productions. (2) The goals of the consumers are to maximize their economic utilities by specifying hourly step functions of demands and maximum buying prices, and bounds on demands. (3) The independent system operator then clears the market taking into account consistency conditions as well as capacity and line losses so as to achieve maximum social welfare. Then, we approach this equilibrium problem using complementarity theory in order to have the capability of imposing constraints on dual variables, i.e., on prices, such as minimum profit conditions for the generating units or maximum cost conditions for the consumers. In this way, given the form of the individual optimization problems, the Karush-Kuhn-Tucker conditions for the generating companies, the consumers and the independent system operator are both necessary and sufficient. The simultaneous solution to all these conditions constitutes a mixed linear complementarity problem. We include minimum profit constraints imposed by the units in the market equilibrium model. These constraints are added as additional constraints to the equivalent quadratic programming problem of the mixed linear complementarity problem previously described. For the sake of clarity, the proposed equilibrium or near-equilibrium is first developed for the particular case considering only one time period. Afterwards, we consider an equilibrium or near-equilibrium applied to a multi-period framework. This model embodies binary

  10. Lewis Acid-Base Adduct Approach for High Efficiency Perovskite Solar Cells.

    Lee, Jin-Wook; Kim, Hui-Seon; Park, Nam-Gyu

    2016-02-16

    Since the first report on the long-term durable 9.7% solid-state perovskite solar cell employing methylammonium lead iodide (CH3NH3PbI3), mesoporous TiO2, and 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-MeOTAD) in 2012, following the seed technologies on perovskite-sensitized liquid junction solar cells in 2009 and 2011, a surge of interest has been focused on perovskite solar cells due to superb photovoltaic performance and extremely facile fabrication processes. The power conversion efficiency (PCE) of perovskite solar cells reached 21% in a very short period of time. Such an unprecedentedly high photovoltaic performance is due to the intrinsic optoelectronic property of organolead iodide perovskite material. Moreover, a high dielectric constant, sub-millimeter scale carrier diffusion length, an underlying ferroelectric property, and ion migration behavior can make organolead halide perovskites suitable for multifunctionality. Thus, besides solar cell applications, perovskite material has recently been applied to a variety fields of materials science such as photodetectors, light emitting diodes, lasing, X-ray imaging, resistive memory, and water splitting. Regardless of application areas, the growth of a well-defined perovskite layer with high crystallinity is essential for effective utilization of its excellent physicochemical properties. Therefore, an effective methodology for preparation of high quality perovskite layers is required. In this Account, an effective methodology for production of high quality perovskite layers is described, which is the Lewis acid-base adduct approach. In the solution process to form the perovskite layer, the key chemicals of CH3NH3I (or HC(NH2)2I) and PbI2 are used by dissolving them in polar aprotic solvents. Since polar aprotic solvents bear oxygen, sulfur, or nitrogen, they can act as a Lewis base. In addition, the main group compound PbI2 is known to be a Lewis acid. Thus, PbI2 has a chance

  11. NONTRIVIAL EQUILIBRIUM SOLUTIONS FOR A SEMILINEAR REACTION-DIFFUSION SYSTEM

    顾永耕; 孙文俊

    2004-01-01

    By the degree theory on positive cone together with the technique of a priori estimate, the nontrivial equilibrium solutions of a strong nonlinearity and weak coupling reaction diffusion system and the structure of the equilibrium solutions are discussed.

  12. Equilibrium Implications of Fiscal Policy with Tax Evasion

    Busato, Francesco; Chiarini, Bruno; Rey, Guido M.

    This paper studies equilibrium effects of fiscal policy disturbances within a dynamic general equilibrium model where tax evasion and underground activities are explicitly incorporated. There are three mainresults. (i) The underground sector mitigates the distortionary impact of fiscal policies, ...

  13. Hawking-Unruh effect on thermal equilibrium state

    Zhao, Zheng [Beijing Normal Univ. (China)]|[Instituts Internationaux de Physique et de Chimie, Bruxelles (Belgium); Zhu Jianyang [Jiangxi Normal Univ., Nanchang (China); Misra, B. [Jawaharlal Nehru Univ., New-Delhi (India)]|[Instituts Internationaux de Physique et de Chimie, Bruxelles (Belgium)

    1996-04-01

    It is pointed out that the usual (Gibbs) thermal equilibrium state in Minkowski spacetime is no longer a thermal equilibrium state in Kruskal spacetime is not a thermal state for a Schwarzschild observer.

  14. [Principle of genetic equilibrium for two gene loci].

    Pan, Shen-Yuan; Qu, Ai; Hui, Peng; Li, Ai-Ling

    2004-03-01

    Because linkage equilibrium is introduced by directly quoting the conclusions or imprecise mathematical reasoning in most of textbooks, many students are puzzled with the problem of linkage equilibrium when they learn population genetics. Based on the radical conditions of genetic equilibrium, the principle of linkage equilibrium condition and process, for two gene loci is introduced by precise mathematical reasoning. The article may provide reference to teachers and students in the teaching and learning of population genetics. PMID:15639991

  15. Relative profit maximization and Bertrand equilibrium with quadratic cost functions

    Atsuhiro Satoh; Yasuhito Tanaka

    2014-01-01

    We study the Bertrand equilibrium in duopoly in which two firms produce a homogeneous good under quadratic cost functions, and they seek to maximize the weighted sum of their absolute and relative profits. We show that there exists a range of the equilibrium price in duopolistic equilibria. This range of equilibrium price is narrower and lower than the range of the equilibrium price in duopolistic equilibria under pure absolute profit maximization, and the larger the weight on the relative pr...

  16. A new perspective to rational expectations: Maximin rational expectations equilibrium

    Castro, Luciano I.; Pesce, Marialaura; Nicholas C. Yannelis

    2010-01-01

    We introduce a new notion of rational expectations equilibrium (REE) called maximin rational expectations equilibrium (MREE), which is based on the maximin expected utility (MEU) formulation. In particular, agents maximize maximin expected utility conditioned on their own private information and the information that the equilibrium prices generate. Maximin equilibrium allocations need not to be measurable with respect to the private information of each individual and with respect to the infor...

  17. A Formal Definition of Perfect Bayesian Equilibrium for Extensive Games

    Julio Gonzalez-Diaz; Miguel Melendez-Jimenez

    2007-01-01

    Often, perfect bayesian equilibrium is loosely defined by stating that players should be sequentially rational given some beliefs in which Bayes rule is applied “whenever possible”. We show that there are games in which it is not clear what “whenever possible” means. Then, we provide a simple definition of perfect bayesian equilibrium for general extensive games that refines both weak perfect equilibrium and subgame perfect equilibrium.

  18. Hanging an Airplane: A Case Study in Static Equilibrium

    Katz, Debora M.

    2009-01-01

    Our classrooms are filled with engineering majors who take a semester-long course in static equilibrium. Many students find this class too challenging and drop their engineering major. In our introductory physics class, we often breeze through static equilibrium; to physicists equilibrium is just a special case of Newton's second law. While it is…

  19. Characterization of Feedback Nash Equilibrium for Differential Games

    Averboukh, Yurii

    2010-01-01

    We investigate the set of Nash equilibrium payoffs for two person differential games. The main result of the paper is the characterization of the set of Nash equilibrium payoffs in the terms of nonsmooth analysis. Also we obtain the sufficient conditions for a pair of continuous function provide a Nash equilibrium. This result generalizes the method of system of Hamilton-Jacobi equations.

  20. Towards breaking temperature equilibrium in multi-component Eulerian schemes

    Grove, John W [Los Alamos National Laboratory; Masser, Thomas [Los Alamos National Laboratory

    2009-01-01

    We investigate the effects ofthermal equilibrium on hydrodynamic flows and describe models for breaking the assumption ofa single temperature for a mixture of components in a cell. A computational study comparing pressure-temperature equilibrium simulations of two dimensional implosions with explicit front tracking is described as well as implementation and J-D calculations for non-equilibrium temperature methods.

  1. 14 CFR 67.305 - Ear, nose, throat, and equilibrium.

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.305..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a third-class airman...) 35 50 50 60 (b) No disease or condition of the middle or internal ear, nose, oral cavity, pharynx,...

  2. 14 CFR 67.205 - Ear, nose, throat, and equilibrium.

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.205..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a second-class airman...) 35 50 50 60 (b) No disease or condition of the middle or internal ear, nose, oral cavity, pharynx,...

  3. 14 CFR 67.105 - Ear, nose, throat, and equilibrium.

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Ear, nose, throat, and equilibrium. 67.105..., nose, throat, and equilibrium. Ear, nose, throat, and equilibrium standards for a first-class airman... internal ear, nose, oral cavity, pharynx, or larynx that— (1) Interferes with, or is aggravated by,...

  4. Thermodynamical equilibrium and the thermal curve

    The study carried out recently by INDRA collaboration on the reactions Ar + Ni at 52 to 95 A.MeV has indicated the formation of a quasi-projectile characterized by an excitation energy up to 25 MeV/N. The decay products are emitted isotropically, the spectra have about the same slope and the partition are independent of incident energy. These facts suggest an equilibrium de-excitation even at excitation energies corresponding to temperatures far from the critical temperature of a finite nucleus. To establish the formation of such a super-critical gas we have compared the data with a simple model of instant multifragmentation in thermodynamical equilibrium including the discrete excited states as well as a first-order correction to the perfect gas equation of state for freeze-out configurations. The model predictions were compared with the experimental multiplicities measured in the de-excitation of the quasi-projectile formed in the reaction Ar + Ni at 95 MeV/u. The fairly good reproduction of the high energy data indicates that the hypothesis of thermodynamical equilibrium is realistic even in the energy domain were this hypothesis is most vulnerable due to the extremely short times of formation and de-excitation of sources. To search for the signature of the possible liquid-gas phase transition i.e. the slope of the functional relation between the temperature and excitation energy (thermal curve) several thermometers were proposed. A comparison of the data with the model predictions shows that inside the validity range of the model (ε* > 10 A.MeV) all the temperatures obtained are well reproduced. A slight change in the slope observed at around 9 MeV excitation energy which could indicate the phase transition is currently under study

  5. Equilibrium and shot noise in mesoscopic systems

    Within the last decade, there has been a resurgence of interest in the study of noise in Mesoscopic devices, both experimentally and theoretically. Noise in solid state devices can have different origins: there is 1/f noise, which is believed to arise from fluctuations in the resistance of the sample due to the motion of impurities. On top of this contribution is a frequency independent component associated with the stochastic nature of electron transport, which will be the focus of this paper. If the sample considered is small enough that dephasing and inelastic effects can be neglected, equilibrium (thermal) and excess noise can be completely described in terms of the elastic scattering properties of the sample. As mentioned above, noise arises as a consequence of random processes governing the transport of electrons. Here, there are two sources of randomness: first, electrons incident on the sample occupy a given energy state with a probability given by the Fermi-Dirac distribution function. Secondly, electrons can be transmitted across the sample or reflected in the same reservoir where they came from with a probability given by the quantum mechanical transmission/reflection coefficients. Equilibrium noise refers to the case where no bias voltage is applied between the leads connected to the sample, where thermal agitation alone allows the electrons close to the Fermi level to tunnel through the sample. In general, equilibrium noise is related to the conductance of the sample via the Johnson-Nyquist formula. In the presence of a bias, in the classical regime, one expects to recover the full shot noise 2I >= 2IΔμ as was observed a long time ago in vacuum diodes. In the Mesoscopic regime, however, excess noise is reduced below the shot noise level. The author introduces a more intuitive picture, where the current passing through the device is a superposition of pulses, or electron wave packets, which can be transmitted or reflected

  6. Equilibrium and shot noise in mesoscopic systems

    Martin, T.

    1994-10-01

    Within the last decade, there has been a resurgence of interest in the study of noise in Mesoscopic devices, both experimentally and theoretically. Noise in solid state devices can have different origins: there is 1/f noise, which is believed to arise from fluctuations in the resistance of the sample due to the motion of impurities. On top of this contribution is a frequency independent component associated with the stochastic nature of electron transport, which will be the focus of this paper. If the sample considered is small enough that dephasing and inelastic effects can be neglected, equilibrium (thermal) and excess noise can be completely described in terms of the elastic scattering properties of the sample. As mentioned above, noise arises as a consequence of random processes governing the transport of electrons. Here, there are two sources of randomness: first, electrons incident on the sample occupy a given energy state with a probability given by the Fermi-Dirac distribution function. Secondly, electrons can be transmitted across the sample or reflected in the same reservoir where they came from with a probability given by the quantum mechanical transmission/reflection coefficients. Equilibrium noise refers to the case where no bias voltage is applied between the leads connected to the sample, where thermal agitation alone allows the electrons close to the Fermi level to tunnel through the sample. In general, equilibrium noise is related to the conductance of the sample via the Johnson-Nyquist formula. In the presence of a bias, in the classical regime, one expects to recover the full shot noise < {Delta}{sup 2}I >= 2I{Delta}{mu} as was observed a long time ago in vacuum diodes. In the Mesoscopic regime, however, excess noise is reduced below the shot noise level. The author introduces a more intuitive picture, where the current passing through the device is a superposition of pulses, or electron wave packets, which can be transmitted or reflected.

  7. Do intertidal flats ever reach equilibrium?

    Maan, D. C.; Prooijen, B. C.; Wang, Z. B.; De Vriend, H. J.

    2015-11-01

    Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the basic processes and feedback mechanisms underlying the long-term behavior of the intertidal system, restricting ourselves to unvegetated intertidal flats that are controlled by cross-shore tidal currents and wind waves and applying a 1-D cross-shore morphodynamic model. The results indicate that by an adjustment of the profile slope and shape, an initial imbalance between deposition and erosion is minimized within a few decades. What follows is a state of long-term seaward progradation or landward retreat of the intertidal flat, in which the cross-shore profile shape is largely maintained and the imbalance between deposition and erosion is not further reduced. These long-term trends can be explained by positive feedbacks from the morphology onto the hydrodynamic forces over the flat: initial accretion (erosion) decreases (increases) the shear stresses over the flat, which induces further accretion (erosion). This implies that a static equilibrium state cannot exist; the flat either builds out or retreats. The modeled behavior is in accordance with observations in the Yangtze Estuary. To treat these unbalanced systems with a one-dimensional numerical model, we propose a moving (Lagrangian) framework in which a stable cross-sectional shape and progradation speed can be derived for growing tidal flats, as a function of the wave climate and the sediment concentration in deeper water.

  8. Multicomponent Equilibrium Models for Testing Geothermometry Approaches

    Carl D. Palmer; Robert W. Smith; Travis L. McLing

    2013-02-01

    Geothermometry is an important tool for estimating deep reservoir temperature from the geochemical composition of shallower and cooler waters. The underlying assumption of geothermometry is that the waters collected from shallow wells and seeps maintain a chemical signature that reflects equilibrium in the deeper reservoir. Many of the geothermometers used in practice are based on correlation between water temperatures and composition or using thermodynamic calculations based a subset (typically silica, cations or cation ratios) of the dissolved constituents. An alternative approach is to use complete water compositions and equilibrium geochemical modeling to calculate the degree of disequilibrium (saturation index) for large number of potential reservoir minerals as a function of temperature. We have constructed several “forward” geochemical models using The Geochemist’s Workbench to simulate the change in chemical composition of reservoir fluids as they migrate toward the surface. These models explicitly account for the formation (mass and composition) of a steam phase and equilibrium partitioning of volatile components (e.g., CO2, H2S, and H2) into the steam as a result of pressure decreases associated with upward fluid migration from depth. We use the synthetic data generated from these simulations to determine the advantages and limitations of various geothermometry and optimization approaches for estimating the likely conditions (e.g., temperature, pCO2) to which the water was exposed in the deep subsurface. We demonstrate the magnitude of errors that can result from boiling, loss of volatiles, and analytical error from sampling and instrumental analysis. The estimated reservoir temperatures for these scenarios are also compared to conventional geothermometers. These results can help improve estimation of geothermal resource temperature during exploration and early development.

  9. Hot nuclear matter and thermodynamical equilibrium

    Quasi-complete events from collisions between 36Ar and 58Ni corresponding to vaporized sources have been detected with the multidetector INDRA over the excitation energy range 10 - 28 AMeV. For the first time complete information concerning kinematical properties of emitted particles and chemical composition (mean values but also variances) are derived. Despite the very extreme conditions in which such sources are produced (binary collisions with short reaction times and source life-times), their properties are in agreement with the results of a statistical model including a final state excluded volume interaction and describing a gas of fermions and bosons in thermodynamical equilibrium. (authors)

  10. Non-equilibrium soft matter physics

    Ota, T

    2012-01-01

    Soft matter is a concept which covers polymers, liquid crystals, colloids, amphiphilic molecules, glasses, granular and biological materials. One of the fundamental characteristic features of soft matter is that it exhibits various mesoscopic structures originating from a large number of internal degrees of freedom of each molecule. Due to such intermediate structures, soft matter can easily be brought into non-equilibrium states and cause non-linear responses by imposing external fields such as an electric field, a mechanical stress or a shear flow. Volume 4 of the series in Soft Condensed Ma

  11. Approach to Equilibrium in the Micromaser

    Leary, D; Carrington, M E; Kobes, R L; Kunstatter, G

    2001-01-01

    We examine the approach to equilibrium of the micromaser. Analytic methods are first used to show that for large times (i.e. many atoms) the convergence is governed by the next to leading eigenvalue of the corresponding discrete evolution matrix. The model is then studied numerically. The numerical results confirm the phase structure expected from analytic approximation methods and agree for large times with the analysis of Elmfors et al in terms of the continuous master equation. For short times, however, we see evidence for interesting new structure not previously reported in the literature.

  12. The Optimal Nash Equilibrium Strategies Under Competition

    孟力; 王崇喜; 汪定伟; 张爱玲

    2004-01-01

    This paper presented a game theoretic model to study the competition for a single investment oppertunity under uncertainty. It models the hazard rate of investment as a function of competitors' trigger level. Under uncertainty and different information structure, the option and game theory was applied to researching the optimal Nash equilibrium strategies of one or more firm. By means of Matlab software, the paper simulates a real estate developing project example and illustrates how parameter affects investment strategies. The paper's work will contribute to the present investment practice in China.

  13. Equilibrium Correlations in a Clustering Universe

    张航; 黄霞; 李晓卿

    2003-01-01

    It is shown that the observed result of the two-point galaxy correlation function and the three-point correlation function in the Universe agrees with a quasi-equilibrium assumption of mass distribution.Utilizing the form of the three-point correlation,we find that the two-point correlation function can be obtained by solving an equation derived from maximizing entropy under some constraints in a self-gravitating particle model.A generalized non-extensive entropy is also introduced to improve our result.

  14. Vectorization of MHD equilibrium and stability codes

    An MHD equilibrium code (SELENE) and a stability code (ERATO-J) are extensively used for the analysis of ideal MHD beta limit of a tokamak plasma. High efficiency is required for the analysis of experimental data and the design of the next step fusion experimental devices. In the report, the methods of vectorization are described as well as the basic equations and numerical methods. Vectorization reduces the comptational time to about a third through a quarter of the original version on Fujitsu VP-100. (author)

  15. Charge-exchange straggling in equilibrium

    Sigmund, P. [Department of Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M (Denmark); Osmani, O. [Department of Physics, University of Duisburg-Essen, D-47048 Duisburg (Germany); Department of Physics, University of Kaiserslautern and Research Center OPTIMAS, D-67653 Kaiserslautern (Germany); Schinner, A. [Institut fuer Experimentalphysik, Johannes, Kepler Universitaet, A-4040 Linz (Austria)

    2011-05-01

    A general expression has been derived that allows computation of charge-exchange straggling of swift heavy ions when many charge states are involved. Charge exchange is found to hinge on the variation of the stopping cross section with the ion charge and on the transient behavior of the charge population as a function of traveled pathlength. These effects appear factorized in the final formula. The focus of this paper is on straggling in charge equilibrium. The case of MeV/u sulfur ions in carbon has been used as an illustration. Charge-exchange straggling is found to be dominating straggling over a considerable range of beam energies.

  16. Measuring productivity differences in equilibrium search models

    Lanot, Gauthier; Neumann, George R.

    1996-01-01

    Equilibrium search models require unobserved heterogeneity in productivity to fit observed wage distribution data, but provide no guidance about the location parameter of the heterogeneity. In this paper we show that the location of the productivity heterogeneity implies a mode in a kernel density...... estimate of the wage distribution. The number of such modes and their location are identified using bump hunting techniques due to Silverman (1981). These techniques are applied to Danish panel data on workers and firms. These estimates are used to assess the importance of employer wage policy....

  17. Exercise training of late-pregnant and nonpregnant dairy cows affects physical fitness and acid-base homeostasis.

    Davidson, J A; Beede, D K

    2009-02-01

    The objective was to determine if exercise training improves physical fitness of nonlactating, late-pregnant and nonpregnant multiparous Holstein cows and alters acid-base homeostasis during an exercise test on a treadmill. Twenty-six pairs (each pair having 1 late-pregnant and 1 nonpregnant) of cows were assigned to treatments of exercise training or no exercise. Exercise training was walking (1.25 to 1.5 h at 3.25 km/h) every other day in an outdoor mechanical walker for 70 d. Cows completed treadmill exercise tests on d 0, 30, and 60 of the experiment or about d 70, 40, and 10 before expected parturition of the pregnant cow of each pair. On d 0, physical fitness was similar among all cows based on durations of treadmill tests, heart rates, and acid-base measurements at given workloads (21.1 +/- 0.6 min; 144 +/- 2.2 beats per min; plasma lactate 3.1 +/- 1.9 mmol/L; and venous blood pH 7.44 +/- 0.0035, respectively). After 60 d of training, exercised cows walked longer during treadmill exercise tests compared with nonexercised cows (23.7 vs. 18.3 +/- 0.85 min, respectively), indicating greater physical fitness (pooled across pregnancy status). Heart rates and plasma lactate concentrations at given workloads were less (144 vs. 156 +/- 2.7 beats per min; and 1.4 vs. 3.2 +/- 0.24 mmol/L for exercised compared with nonexercised cows, respectively). Additionally, exercised cows more effectively maintained acid-base homeostasis during treadmill tests compared with nonexercised cows. Metabolic, endocrine, and nutritional demands associated with late pregnancy did not affect responses differently to exercise training for late-pregnant compared with nonpregnant cows. Overall, exercise training of late-pregnant and nonpregnant cows for 60 d improved physical fitness. PMID:19164665

  18. Single Sodium Pyruvate Ingestion Modifies Blood Acid-Base Status and Post-Exercise Lactate Concentration in Humans

    Robert A. Olek

    2014-05-01

    Full Text Available This study examined the effect of a single sodium pyruvate ingestion on a blood acid-base status and exercise metabolism markers. Nine active, but non-specifically trained, male subjects participated in the double-blind, placebo-controlled, crossover study. One hour prior to the exercise, subjects ingested either 0.1 g·kg−1 of body mass of a sodium pyruvate or placebo. The capillary blood samples were obtained at rest, 60 min after ingestion, and then three and 15 min after completing the workout protocol to analyze acid-base status and lactate, pyruvate, alanine, glucose concentrations. The pulmonary gas exchange, minute ventilation and the heart rate were measured during the exercise at a constant power output, corresponding to ~90% O2max. The blood pH, bicarbonate and the base excess were significantly higher after sodium pyruvate ingestion than in the placebo trial. The blood lactate concentration was not different after the ingestion, but the post-exercise was significantly higher in the pyruvate trial (12.9 ± 0.9 mM than in the placebo trial (10.6 ± 0.3 mM, p < 0.05 and remained elevated (nonsignificant after 15 min of recovery. The blood pyruvate, alanine and glucose concentrations, as well as the overall pulmonary gas exchange during the exercise were not affected by the pyruvate ingestion. In conclusion, the sodium pyruvate ingestion one hour before workout modified the blood acid-base status and the lactate production during the exercise.

  19. Influence of different storage times and temperatures on blood gas and acid-base balance in ovine venous blood

    H.A. Hussein

    2013-01-01

    Full Text Available The present study was designed to investigate the effects of storage temperature and time on blood gas and acid-base balance of ovine venous blood. Ten clinically healthy sheep were used in this study. A total number of 30 blood samples, were divided into three different groups, and were stored in a refrigerator adjusted to +4 ºC (Group I, n = 10, at RT of about 22-25 ºC (Group II, n = 10 and in an incubator adjusted to 37 ºC (Group III, n = 10 for up to 48 h. Blood samples were analysed for blood gas and acid-base indices at 0, 1, 2, 3, 4, 5, 6, 12, 24 and 48 h of storage. In comparison to the baseline value (0, there were significant decreases of blood pH of samples stored at RT and in the incubator after 1 h (p<0.05, the pH value of refrigerated blood samples exhibited insignificant changes during the study (p<0.05. Mean values of pCO2 showed a significant increase in Group I and Group III after 1 h then a progressive decrease after 12 h in all Groups. Mean pO2 values were significantly higher for Group I after 2 h and for Groups II and III after 1 h (p<0.05. In general, base excess decreased significantly for all the groups during the study especially in Groups II and III. In comparison with baseline values, in all groups, bicarbonate (HCO3 increased between 1 h and 6 h (p<0.05, and later decreased at the end of the study (p<0.05. In conclusion, status of acid-base indices of the samples stored at refrigerator and RT were found within normal reference range and it may be of clinical diagnostic use for up to 6 h.

  20. Theoretical Studies of Aqueous Systems above 25 deg C. 1. Fundamental Concepts for Equilibrium Diagrams and some General Features of the Water System

    The illustration of thermodynamic data on aqueous systems is discussed and diagrams are described that are useful for bringing together the large numbers of data that are relevant to technological problems such as corrosion, mass-transport and deposition. Two kinds of logarithmic equilibrium diagram are particularly useful, namely, diagrams depicting the variation with pH or pe of the concentrations of ionic species relative to that of a chosen reference ion and diagrams depicting the fields of conditions of pH and pe in which the various species in any given system predominate or are stable. Such diagrams clearly and concisely illustrate the data and greatly simplify the comparison of the states of a system at different temperatures. Estimates of the equilibrium constants for the redox and the acid-base dissociation of water up to 375 C are reported and some general features of aqueous systems at elevated temperatures are discussed

  1. Equilibrium and pre-equilibrium emissions in proton-induced reactions on 203,205Tl

    A Kaplan; A Aydin; E Tel; B Şarer

    2009-02-01

    In this study, the excitation functions for the reactions 203Tl(, )203Pb, 203Tl(, 3)203Pb, 203Tl(, 2)202Pb, 205Tl(, 4)202Pb, 203Tl(, 3)201Pb, 205Tl(, 5)201Pb, 203Tl(, 4)200Pb and 205Tl(, 6)200Pb have been calculated using pre-equilibrium and equilibrium reaction mechanisms. Calculated results based on hybrid model, geometry-dependent hybrid model and cascade-exciton model have been compared with the experimental data.

  2. Yarrowia lipolytica as an oleaginous cell factory platform for the production of fatty acid-based biofuel and bioproducts

    Ali eAbghari

    2014-06-01

    Full Text Available Today’s biotechnologists seek new biocatalysts to meet the growing demand for the bioproducts. This review critically evaluates the potential use of Y. lipolytica as an oleaginous cell factory platform. This yeast has undergone extensive modifications for converting a wide range of hydrophobic and hydrophilic biomass, including alkane, oil, glycerol and sugars to fatty acid-based products. This article highlights challenges in the development of this platform and provides an overview of strategies to enhance its potential in the sustainable production of biodiesel, functional dietary lipid compounds and other value-added oleochemical compounds. Future applications of the recombinant Y. lipolytica platform are also discussed.

  3. An exploratory study into students' conceptual understanding of acid/base principles associated with chemical buffer systems

    MacGowan, Catherine Elizabeth

    The overall objective of this research project was to provide an insight into students' conceptual understanding of acid/base principles as it relates to the comprehension and correct application of scientific concepts during a problem-solving activity. The difficulties experienced learning science and in developing appropriate problem-solving strategies most likely are predetermined by students' existing conceptual and procedural knowledge constructs; with the assimilation of newly acquired knowledge hindering or aiding the learning process. Learning chemistry requires a restructuring of content knowledge which will allow the individual to assemble and to integrate his/her own perception of science with instructional knowledge. The epistemology of constructivism, the theoretical grounding for this research project, recognizes the student's role as an active participant in the learning process. The study's design was exploratory in nature and descriptive in design. The problem-solving activity, the preparation of a chemical buffer solution at pH of 9, was selected and modified to reflect and meet the study's objective. Qualitative research methods (i.e., think aloud protocols, retrospective interviews, survey questionnaires such as the Scale of Intellectual Development (SID), and archival data sources) were used in the collection and assessment of data. Given its constructivist grounding, simplicity, and interpretative view of knowledge acquisition and learning of collegiate aged individuals, the Perry Intellectual and Ethical Development Model (1970) was chosen as the applied model for evaluation student cognition. The study's participants were twelve traditional college age students from a small, private liberal arts college. All participants volunteered for the project and had completed or were completing a general college chemistry course at the time of the project. Upon analysis of the data the following observations and results were noted: (1) students

  4. Effect of modification with scandium oxide on the hydroxyl coating and acid-base properties of the zirconium dioxide surface

    Physicochemical properties of Sc2O3 - ZrO2 system surface were studied by the method of IR spectroscopy, surface properties of the samples prepared by coprecipitation and by impregnation method were compared. Influence of scandium oxide concentration as a modifying component on hydroxylic coating and acid-base properties of zirconium dioxide surface was ascertained. It is shown that zirconium dioxide modification by scandium does not give rise to the appearance of new types of Lewis acid centers. Modifying effect of scandium was compared to that of yttrium and lanthanum

  5. The Importance of the Ionic Product for Water to Understand the Physiology of the Acid-Base Balance in Humans

    Adeva-Andany, María M.; Natalia Carneiro-Freire; Cristóbal Donapetry-García; Eva Rañal-Muíño; Yosua López-Pereiro

    2014-01-01

    Human plasma is an aqueous solution that has to abide by chemical rules such as the principle of electrical neutrality and the constancy of the ionic product for water. These rules define the acid-base balance in the human body. According to the electroneutrality principle, plasma has to be electrically neutral and the sum of its cations equals the sum of its anions. In addition, the ionic product for water has to be constant. Therefore, the plasma concentration of hydrogen ions depends on th...

  6. Non-equilibrium many body dynamics

    This Riken BNL Research Center Symposium on Non-Equilibrium Many Body Physics was held on September 23-25, 1997 as part of the official opening ceremony of the Center at Brookhaven National Lab. A major objective of theoretical work at the center is to elaborate on the full spectrum of strong interaction physics based on QCD, including the physics of confinement and chiral symmetry breaking, the parton structure of hadrons and nuclei, and the phenomenology of ultra-relativistic nuclear collisions related to the up-coming experiments at RHIC. The opportunities and challenges of nuclear and particle physics in this area naturally involve aspects of the many body problem common to many other fields. The aim of this symposium was to find common theoretical threads in the area of non-equilibrium physics and modern transport theories. The program consisted of invited talks on a variety topics from the fields of atomic, condensed matter, plasma, astrophysics, cosmology, and chemistry, in addition to nuclear and particle physics. Separate abstracts have been indexed into the database for contributions to this workshop

  7. Structural design using equilibrium programming formulations

    Scotti, Stephen J.

    1995-06-01

    Solutions to increasingly larger structural optimization problems are desired. However, computational resources are strained to meet this need. New methods will be required to solve increasingly larger problems. The present approaches to solving large-scale problems involve approximations for the constraints of structural optimization problems and/or decomposition of the problem into multiple subproblems that can be solved in parallel. An area of game theory, equilibrium programming (also known as noncooperative game theory), can be used to unify these existing approaches from a theoretical point of view (considering the existence and optimality of solutions), and be used as a framework for the development of new methods for solving large-scale optimization problems. Equilibrium programming theory is described, and existing design techniques such as fully stressed design and constraint approximations are shown to fit within its framework. Two new structural design formulations are also derived. The first new formulation is another approximation technique which is a general updating scheme for the sensitivity derivatives of design constraints. The second new formulation uses a substructure-based decomposition of the structure for analysis and sensitivity calculations. Significant computational benefits of the new formulations compared with a conventional method are demonstrated.

  8. Equilibrium crystal phases of triblock Janus colloids.

    Reinhart, Wesley F; Panagiotopoulos, Athanassios Z

    2016-09-01

    Triblock Janus colloids, which are colloidal spheres decorated with attractive patches at each pole, have recently generated significant interest as potential building blocks for functional materials. Their inherent anisotropy is known to induce self-assembly into open structures at moderate temperatures and pressures, where they are stabilized over close-packed crystals by entropic effects. We present a numerical investigation of the equilibrium phases of triblock Janus particles with many different patch geometries in three dimensions, using Monte Carlo simulations combined with free energy calculations. In all cases, we find that the free energy difference between crystal polymorphs is less than 0.2 kBT per particle. By varying the patch fraction and interaction range, we show that large patches stabilize the formation of structures with four bonds per patch over those with three. This transition occurs abruptly above a patch fraction of 0.30 and has a strong dependence on the interaction range. Furthermore, we find that a short interaction range favors four bonds per patch, with longer range increasingly stabilizing structures with only three bonds per patch. By quantifying the effect of patch geometry on the stability of the equilibrium crystal structures, we provide insights into the fundamental design rules for constructing complex colloidal crystals. PMID:27609002

  9. Equilibrium spin pulsars unite neutron star populations

    Ho, Wynn C G; Coe, M J; Andersson, Nils

    2014-01-01

    Many pulsars are formed with a binary companion from which they can accrete matter. Torque exerted by accreting matter can cause the pulsar spin to increase or decrease, and over long times, an equilibrium spin rate is achieved. Application of accretion theory to these systems provides a probe of the pulsar magnetic field. We compare the large number of recent torque measurements of accreting pulsars with a high-mass companion to the standard model for how accretion affects the pulsar spin period. We find that many long spin period (P > 100 s) pulsars must possess either extremely weak (B 10^14 G) magnetic fields. We argue that the strong-field solution is more compelling, in which case these pulsars are near spin equilibrium. Our results provide evidence for a fundamental link between pulsars with the slowest spin periods and strong magnetic fields around high-mass companions and pulsars with the fastest spin periods and weak fields around low-mass companions. The strong magnetic fields also connect our pul...

  10. Gyrokinetic Statistical Absolute Equilibrium and Turbulence

    Jian-Zhou Zhu and Gregory W. Hammett

    2011-01-10

    A paradigm based on the absolute equilibrium of Galerkin-truncated inviscid systems to aid in understanding turbulence [T.-D. Lee, "On some statistical properties of hydrodynamical and magnetohydrodynamical fields," Q. Appl. Math. 10, 69 (1952)] is taken to study gyrokinetic plasma turbulence: A finite set of Fourier modes of the collisionless gyrokinetic equations are kept and the statistical equilibria are calculated; possible implications for plasma turbulence in various situations are discussed. For the case of two spatial and one velocity dimension, in the calculation with discretization also of velocity v with N grid points (where N + 1 quantities are conserved, corresponding to an energy invariant and N entropy-related invariants), the negative temperature states, corresponding to the condensation of the generalized energy into the lowest modes, are found. This indicates a generic feature of inverse energy cascade. Comparisons are made with some classical results, such as those of Charney-Hasegawa-Mima in the cold-ion limit. There is a universal shape for statistical equilibrium of gyrokinetics in three spatial and two velocity dimensions with just one conserved quantity. Possible physical relevance to turbulence, such as ITG zonal flows, and to a critical balance hypothesis are also discussed.

  11. Gyrokinetic Statistical Absolute Equilibrium and Turbulence

    A paradigm based on the absolute equilibrium of Galerkin-truncated inviscid systems to aid in understanding turbulence (T.-D. Lee, 'On some statistical properties of hydrodynamical and magnetohydrodynamical fields,' Q. Appl. Math. 10, 69 (1952)) is taken to study gyrokinetic plasma turbulence: A finite set of Fourier modes of the collisionless gyrokinetic equations are kept and the statistical equilibria are calculated; possible implications for plasma turbulence in various situations are discussed. For the case of two spatial and one velocity dimension, in the calculation with discretization also of velocity v with N grid points (where N + 1 quantities are conserved, corresponding to an energy invariant and N entropy-related invariants), the negative temperature states, corresponding to the condensation of the generalized energy into the lowest modes, are found. This indicates a generic feature of inverse energy cascade. Comparisons are made with some classical results, such as those of Charney-Hasegawa-Mima in the cold-ion limit. There is a universal shape for statistical equilibrium of gyrokinetics in three spatial and two velocity dimensions with just one conserved quantity. Possible physical relevance to turbulence, such as ITG zonal flows, and to a critical balance hypothesis are also discussed.

  12. Equilibrium states of homogeneous sheared compressible turbulence

    M. Riahi

    2011-06-01

    Full Text Available Equilibrium states of homogeneous compressible turbulence subjected to rapid shear is studied using rapid distortion theory (RDT. The purpose of this study is to determine the numerical solutions of unsteady linearized equations governing double correlations spectra evolution. In this work, RDT code developed by authors solves these equations for compressible homogeneous shear flows. Numerical integration of these equations is carried out using a second-order simple and accurate scheme. The two Mach numbers relevant to homogeneous shear flow are the turbulent Mach number Mt, given by the root mean square turbulent velocity fluctuations divided by the speed of sound, and the gradient Mach number Mg which is the mean shear rate times the transverse integral scale of the turbulence divided by the speed of sound. Validation of this code is performed by comparing RDT results with direct numerical simulation (DNS of [A. Simone, G.N. Coleman, and C. Cambon, Fluid Mech. 330, 307 (1997] and [S. Sarkar, J. Fluid Mech. 282, 163 (1995] for various values of initial gradient Mach number Mg0. It was found that RDT is valid for small values of the non-dimensional times St (St 10 in particular for large values of Mg0. This essential feature justifies the resort to RDT in order to determine equilibrium states in the compressible regime.

  13. In command of non-equilibrium.

    Roduner, Emil; Radhakrishnan, Shankara Gayathri

    2016-05-21

    The second law of thermodynamics is well known for determining the direction of spontaneous processes in the laboratory, life and the universe. It is therefore often called the arrow of time. Less often discussed but just as important is the effect of kinetic barriers which intercept equilibration and preserve highly ordered, high energy non-equilibrium states. Examples of such states are many modern materials produced intentionally for technological applications. Furthermore, all living organisms fuelled directly by photosynthesis and those fuelled indirectly by living on high energy nutrition represent preserved non-equilibrium states. The formation of these states represents the local reversal of the arrow of time which only seemingly violates the second law. It has been known since the seminal work of Prigogine that the stabilisation of these states inevitably requires the dissipation of energy in the form of waste heat. It is this feature of waste heat dissipation following the input of energy that drives all processes occurring at a non-zero rate. Photosynthesis, replication of living organisms, self-assembly, crystal shape engineering and distillation have this principle in common with the well-known Carnot cycle in the heat engine. Drawing on this analogy, we subsume these essential and often sophisticated driven processes under the term machinery of life. PMID:27146424

  14. The equilibrium crystal shape of nickel

    Highlights: → The ECS of pure Ni is completely facetted with both dense and high-index planes. → The partial pressure of oxygen has a significant effect on the surface anisotropy. → The addition of Fe decreased the anisotropy and de-stabilized high-index planes. → During solid dewetting nucleation barriers prevent equilibration of the top facet. - Abstract: The crystal shape of Ni particles, dewetted in the solid state on sapphire substrates, was examined as a function of the partial pressure of oxygen (P(O2)) and iron content using scanning and transmission electron microscopy. The chemical composition of the surface was characterized by atom-probe tomography. Unlike other face-centered cubic (fcc) equilibrium crystal shapes, the Ni crystals containing little or no impurities exhibited a faceted shape, indicating large surface anisotropy. In addition to the {1 1 1}, {1 0 0} and {1 1 0} facets, which are usually present in the equilibrium crystal shape of fcc metals, high-index facets were identified such as {1 3 5} and {1 3 8} at low P(O2), and {0 1 2} and {0 1 3} at higher P(O2). The presence of iron altered the crystal shape into a truncated sphere with only facets parallel to denser planes. The issue of particle equilibration is discussed specifically for the case of solid-state dewetting.

  15. Chemical Equilibrium of Dust at Low Temperature

    Ferguson, Jason W.; Alexander, David R.; Allard, France; Hauschildt, Peter H.

    The opacity of material is required whenever the detailed transfer of radiation through a gas is modeled. Computation of the opacity requires both a thorough knowledge of the chemical state of the gas (species populations) and the absorption/scattering behavior of those species. At low temperatures the equation of state (EOS) calculations become particularly complex. Our EOS computations assume chemical equilibrium and include over 600 solid and liquid species with data mainly from the JANAF database. We will present and discuss our EOS computations for gas temperatures from 2000 K to 300 K and a wide range of gas densities, pressures and chemical compositions. Large discontinuities in species abundances are seen when an individual grain species condenses. It has been known for some time that solid silicate and iron particles play important roles in the chemical equilibrium and opacity of a cool gas. Many other condensed species, including Al2 O3, CaTiO3, and even carbon at very low temperature, can play equally important roles.

  16. Equilibrium Model of Precipitation in Microalloyed Steels

    Xu, Kun; Thomas, Brian G.; O'Malley, Ron

    2011-02-01

    The formation of precipitates during thermal processing of microalloyed steels greatly influences their mechanical properties. Precipitation behavior varies with steel composition and temperature history and can lead to beneficial grain refinement or detrimental transverse surface cracks. This work presents an efficient computational model of equilibrium precipitation of oxides, sulfides, nitrides, and carbides in steels, based on satisfying solubility limits including Wagner interaction between elements, mutual solubility between precipitates, and mass conservation of alloying elements. The model predicts the compositions and amounts of stable precipitates for multicomponent microalloyed steels in liquid, ferrite, and austenite phases at any temperature. The model is first validated by comparing with analytical solutions of simple cases, predictions using the commercial package JMat-PRO, and previous experimental observations. Then it is applied to track the evolution of precipitate amounts during continuous casting of two commercial steels (1004 LCAK and 1006Nb HSLA) at two different casting speeds. This model is easy to modify to incorporate other precipitates, or new thermodynamic data, and is a useful tool for equilibrium precipitation analysis.

  17. Structural design using equilibrium programming formulations

    Scotti, Stephen J.

    1995-01-01

    Solutions to increasingly larger structural optimization problems are desired. However, computational resources are strained to meet this need. New methods will be required to solve increasingly larger problems. The present approaches to solving large-scale problems involve approximations for the constraints of structural optimization problems and/or decomposition of the problem into multiple subproblems that can be solved in parallel. An area of game theory, equilibrium programming (also known as noncooperative game theory), can be used to unify these existing approaches from a theoretical point of view (considering the existence and optimality of solutions), and be used as a framework for the development of new methods for solving large-scale optimization problems. Equilibrium programming theory is described, and existing design techniques such as fully stressed design and constraint approximations are shown to fit within its framework. Two new structural design formulations are also derived. The first new formulation is another approximation technique which is a general updating scheme for the sensitivity derivatives of design constraints. The second new formulation uses a substructure-based decomposition of the structure for analysis and sensitivity calculations. Significant computational benefits of the new formulations compared with a conventional method are demonstrated.

  18. Phase equilibrium condition of marine carbon dioxide hydrate

    Highlights: ► CO2 hydrate phase equilibrium was studied in simulated marine sediments. ► CO2 hydrate equilibrium temperature in NaCl and submarine pore water was depressed. ► Coarse-grained silica sand does not affect CO2 hydrate phase equilibrium. ► The relationship between equilibrium temperature and freezing point was discussed. - Abstract: The phase equilibrium of ocean carbon dioxide hydrate should be understood for ocean storage of carbon dioxide. In this paper, the isochoric multi-step heating dissociation method was employed to investigate the phase equilibrium of carbon dioxide hydrate in a variety of systems (NaCl solution, submarine pore water, silica sand + NaCl solution mixture). The experimental results show that the depression in the phase equilibrium temperature of carbon dioxide hydrate in NaCl solution is caused mainly by Cl− ion. The relationship between the equilibrium temperature and freezing point in NaCl solution was discussed. The phase equilibrium temperature of carbon dioxide hydrate in submarine pore water is shifted by −1.1 K to lower temperature region than that in pure water. However, the phase equilibrium temperature of carbon dioxide hydrate in mixture samples of coarsed-grained silica sand and NaCl solution is in agreement with that in NaCl solution with corresponding concentrations. The relationship between the equilibrium temperature and freezing point in mixture samples was also discussed.

  19. Housing Price Fluctuations Across China: An Equilibrium Mechanism Perspective

    ZHANG Hong; WENG Shaoqun; ZHOU Xuan

    2007-01-01

    The mechanisms affecting housing prices were studied using the equilibrium housing prices based on classic supply/demand theory. The fluctuations of the actual housing prices were then analyzed relative to the equilibrium prices. The equilibrium prices for each area were calculated from economic statistics and housing prices in 35 China metropolitan areas. The fluctuations of the actual prices are then manifested as functions of the equilibrium price, the mean reversion, and the autocorrelation coefficient. The results show that the equilibrium prices are determined by the basic economic conditions in China and that the equilibrium prices greatly affect the fluctuation of the actual prices, which return to the equilibrium price through self-adjustments. The data also shows that the actual prices in China have the trend of continuing to rise in the future.

  20. Separate Determination of Borohydride, Borate, Hydroxide, and Carbonate in the Borohydride Fuel Cell by Acid-Base and Iodometric Potentiometric Titration

    Churikov, A. V.; S. L. Shmakov; Romanova, V. O.; Zapsis, K. V.; Ushakov, A. V.; Ivanishchev, A. V.; Churikov, M. A.

    2014-01-01

    A methodology for quantitative chemical analysis of the complex “borohydride-borate-hydroxide-carbonate-water” mixtures used as fuel in the borohydride fuel cell was developed and optimized. The methodology includes the combined usage of the acid-base and iodometric titration methods. The acid-base titration method, which simultaneously uses the technique of differentiation and computer simulation of titration curves, allows one to determine the contents of hydroxide (alkali), carbonate, and ...

  1. Universality in equilibrium and away from it: A personal perspective

    In this talk/paper I discuss the concept of universality in phase transitions and the question of whether universality classes are more robust in equilibrium than away from it. In both of these situations, the main ingredients determining universality are symmetries, conservation laws, the dimension of the space and of the order-parameter and the presence of long-range interactions or quenched disorder. The existence of detailed-balance and fluctuation-dissipation theorems imposes severe constraints on equilibrium systems, allowing to define universality classes in a very robust way; instead, non-equilibrium allows for more variability. Still, quite robust non-equilibrium universality classes have been identified in the last decades. Here, I discuss some examples in which (i) non-equilibrium phase transitions are simply controlled by equilibrium critical points, i.e. non-equilibrium ingredients turn out to be irrelevant in the renormalization group sense and (ii) non-equilibrium situations in which equilibrium seems to come out of the blue, generating an adequate effective description of intrinsically non-equilibrium problems. Afterwards, I shall describe different genuinely non-equilibrium phase transitions in which introducing small, apparently innocuous changes (namely: presence or absence of an underlying lattice, parity conservation in the overall number of particles, existence of an un-accessible vacuum state, deterministic versus stochastic microscopic rules, presence or absence of a Fermionic constraint), the critical behavior is altered, making the case for lack of robustness. However, it will be argued that in all these examples, there is an underlying good reason (in terms of general principles) for universality to be altered. The final conclusions are that: (i) robust universality classes exist both in equilibrium and non-equilibrium; (ii) symmetry and conservation principles are crucial in both, (iii) non-equilibrium allows for more variability (i

  2. Equilibrium and non-equilibrium dynamics simultaneously operate in the Galápagos islands

    Valente, Luis M.; Phillimore, Albert B.; Etienne, Rampal S.

    2015-01-01

    Island biotas emerge from the interplay between colonisation, speciation and extinction and are often the scene of spectacular adaptive radiations. A common assumption is that insular diversity is at a dynamic equilibrium, but for remote islands, such as Hawaii or Galapagos, this idea remains untest

  3. Equilibrium and non-equilibrium cluster phases in colloids with competing interactions.

    Mani, Ethayaraja; Lechner, Wolfgang; Kegel, Willem K; Bolhuis, Peter G

    2014-07-01

    The phase behavior of colloids that interact via competing interactions - short-range attraction and long-range repulsion - is studied by computer simulation. In particular, for a fixed strength and range of repulsion, the effect of the strength of an attractive interaction (ε) on the phase behavior is investigated at various colloid densities (ρ). A thermodynamically stable equilibrium colloidal cluster phase, consisting of compact crystalline clusters, is found below the fluid-solid coexistence line in the ε-ρ parameter space. The mean cluster size is found to linearly increase with the colloid density. At large ε and low densities, and at small ε and high densities, a non-equilibrium cluster phase, consisting of elongated Bernal spiral-like clusters, is observed. Although gelation can be induced either by increasing ε at constant density or vice versa, the gelation mechanism is different in either route. While in the ρ route gelation occurs via a glass transition of compact clusters, gelation in the ε route is characterized by percolation of elongated clusters. This study both provides the location of equilibrium and non-equilibrium cluster phases with respect to the fluid-solid coexistence, and reveals the dependencies of the gelation mechanism on the preparation route. PMID:24824226

  4. Reconstructing equilibrium entropy and enthalpy profiles from non-equilibrium pulling.

    Jeong, Daun; Andricioaei, Ioan

    2013-03-21

    The Jarzynski identity can be applied to instances when a microscopic system is pulled repeatedly but quickly along some coordinate, allowing the calculation of an equilibrium free energy profile along the pulling coordinate from a set of independent non-equilibrium trajectories. Using the formalism of Wiener stochastic path integrals in which we assign temperature-dependent weights to Langevin trajectories, we derive exact formulae for the temperature derivatives of the free energy profile. This leads naturally to analytical expressions for decomposing a free energy profile into equilibrium entropy and internal energy profiles from non-equilibrium pulling. This decomposition can be done from trajectories evolved at a unique temperature without repeating the measurement as done in finite-difference decompositions. Three distinct analytical expressions for the entropy-energy decomposition are derived: using a time-dependent generalization of the weighted histogram analysis method, a quasi-harmonic spring limit, and a Feynman-Kac formula. The three novel formulae of reconstructing the pair of entropy-energy profiles are exemplified by Langevin simulations of a two-dimensional model system prototypical for force-induced biomolecular conformational changes. Connections to single-molecule experimental means to probe the functionals needed in the decomposition are suggested. PMID:23534630

  5. Comparative evaluation of kinetic, equilibrium and semi-equilibrium models for biomass gasification

    Buragohain, Buljit [Center for Energy, Indian Institute of Technology Guwahati, Guwahati – 781 039, Assam (India); Chakma, Sankar; Kumar, Peeush [Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati – 781 039, Assam (India); Mahanta, Pinakeswar [Center for Energy, Indian Institute of Technology Guwahati, Guwahati – 781 039, Assam (India); Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati – 781 039, Assam (India); Moholkar, Vijayanand S. [Center for Energy, Indian Institute of Technology Guwahati, Guwahati – 781 039, Assam (India); Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati – 781 039, Assam (India)

    2013-07-01

    Modeling of biomass gasification has been an active area of research for past two decades. In the published literature, three approaches have been adopted for the modeling of this process, viz. thermodynamic equilibrium, semi-equilibrium and kinetic. In this paper, we have attempted to present a comparative assessment of these three types of models for predicting outcome of the gasification process in a circulating fluidized bed gasifier. Two model biomass, viz. rice husk and wood particles, have been chosen for analysis, with gasification medium being air. Although the trends in molar composition, net yield and LHV of the producer gas predicted by three models are in concurrence, significant quantitative difference is seen in the results. Due to rather slow kinetics of char gasification and tar oxidation, carbon conversion achieved in single pass of biomass through the gasifier, calculated using kinetic model, is quite low, which adversely affects the yield and LHV of the producer gas. Although equilibrium and semi-equilibrium models reveal relative insensitivity of producer gas characteristics towards temperature, the kinetic model shows significant effect of temperature on LHV of the gas at low air ratios. Kinetic models also reveal volume of the gasifier to be an insignificant parameter, as the net yield and LHV of the gas resulting from 6 m and 10 m riser is same. On a whole, the analysis presented in this paper indicates that thermodynamic models are useful tools for quantitative assessment of the gasification process, while kinetic models provide physically more realistic picture.

  6. A numerical approach to weak Pareto solutions to equilibrium problems with equilibrium constraints

    Červinka, Michal

    2006-01-01

    Roč. 57, č. 7 (2006), s. 14-17. ISSN 1335-3632. [ISCAM 2006. International Conference in Applied Mathematics for undergraduate and graduate students. Bratislava, 07.04.2006-08.04.2006] Institutional research plan: CEZ:AV0Z10750506 Keywords : equilibrium problems with complementarity constraints * multiobjective optimization * variational analysis Subject RIV: BD - Theory of Information

  7. Acid base status in swamp buffaloes (Bubalus Bubalis fed rice straw and concentrate with addition of sodium

    G Joseph

    2001-12-01

    Full Text Available An experiment was conducted to study the addition of NaHCO3 and Na2CO3 on acid-base status in swamp buffaloes, Three fistulated buffaloes were each introduced to dietary treatment control diett (50% rice straw + 50% concentrate, control + \\0% NaHCO3 and diet control + 10% Na2CO3 in two times Latin Square Design. The diets contained 9,7% crude protein and 53% TDN to achieve maintenance requirements of the animals. Parameters measured include (l Fed consumption, water consumption and urine volume. (2 pH in rumen fluid, saliva, bLood and urine, (3 natrium mineral content in rumen fluid, saliva, blood and urine. The results of the experiment showed higher pH in the rumen fluid, saliva, blood and urine of buffaloes due to supplementation of NaHCO3 and Na2CO3, Water consumption and urine volume was significanly increased as the effect of Na supplement. The acid-base status of buffaloes was apparently normal in all animals.

  8. Studies of Modification of Zeolite by Tandem Acid-Base Treatments and its Adsorptions Performance Towards Thorium

    G. Nurliati

    2015-08-01

    Full Text Available Hierarchical zeolite was prepared from natural zeolite using tandem acid-base treatments and applied as adsorbent for Th(IV removal. Natural zeolite occurred naturally as microporous material. It was modified using two familiar methods simultaneously, dealumination and desilication techniques, to change its micropore size into hierarchical pores.. Extensive characterization of both natural and modified zeolites were conducted using XRD, BET, SEM-EDS, and AAS. XRD Patterns of raw, pre-treated , and acid-base tandem modified zeolites show that the modification process has not changed the crystal properties of this material. However, the Si/Al ratio is increased from 6.688 to 11.401 for Na-zeolite (NaZ and modified zeolite, ZA2B respectively. The surface area is increased from 125.4 m2/g (NaZ to 216.8 m2/g (ZA2B, indicative of the creation of mesopore in addition to naturally micropore structure. The application of these zeolite materials as adsorbent were carried out using solution of 50 ppm Th4+measured using UV-Vis spectrophotometer. The UV-Vis result shows that the modified zeolite (ca. 10 mg has higher adsorption capacity than natural zeolite. The adsorption process does not fit into Langmuir and Freundlich isotherm and the adsorption capacity of this material increase from 909 mg/g to 2000 mg/g for NaZ and ZA2B respectively.

  9. Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid base properties on the oxidation of isopropanol

    Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K2CO3 as precipitant. The decomposition of these hydrotalcite precursors at 450 deg C yielded homogeneous MgyAlOx mixed oxides that contain the Al+3 cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR) and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V+5 decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene. (author)

  10. Vanadium oxides supported on hydrotalcite-type precursors: the effect of acid-base properties on the oxidation of isopropanol

    D. M. Meira

    2006-09-01

    Full Text Available Vanadium oxide supported on hydrotalcite-type precursors was studied in the oxidation of isopropanol. Hydrotalcites with different y = Mg/Al ratios were synthesized by the method of coprecipitation nitrates of Mg and Al cations with K2CO3 as precipitant. The decomposition of these hydrotalcite precursors at 450°C yielded homogeneous MgyAlOx mixed oxides that contain the Al+3 cations totally incorporated into the MgO framework. The materials were characterized by chemical analysis, BET superficial area, X-ray diffraction, temperature-programmed reduction (TPR and the reaction of isopropanol, a probe molecule used to evaluate the acid-base properties. The results of TPR showed that the reducibility of V+5 decreased with the increase in magnesium loading in catalysts. The X-ray diffraction patterns of Al-rich hydrotalcite precursors showed the presence of crystalline phases of brucite and gibbsite. It was shown that chemical composition, texture, acid-base properties of the active sites and also Mg/Al ratio strongly affect the formation of the products in the oxidation of isopropanol. The Al-rich catalysts were much more active than the Mg-rich ones, converting isopropanol mainly to propylene.

  11. Effects of ractopamine hydrochloride on performance, rate and variation in feed intake, and acid-base balance in feedlot cattle.

    Abney, C S; Vasconcelos, J T; McMeniman, J P; Keyser, S A; Wilson, K R; Vogel, G J; Galyean, M L

    2007-11-01

    Two experiments evaluated effects of ractopamine hydrochloride (RAC) on performance, intake patterns, and acid-base balance of feedlot cattle. In Exp. 1, 360 crossbred steers (Brangus, British, and British x Continental breeding; initial BW = 545 kg) were used in a study with a 3 x 3 factorial design to study the effects of dose [0, 100, or 200 mg/(steer x d) of RAC] and duration (28, 35, or 42 d) of feeding of RAC in a randomized complete block design (9 treatments, 8 pens/treatment). No dose x duration interactions were detected (P > 0.10). As RAC dose increased, final BW (FBW; P = 0.01), ADG (P 0.10) in feedlot performance, urine pH, blood gas measurements, or variation in intake patterns between RAC and control cattle, but steers fed RAC had increased (P = 0.04) LM area, decreased (P = 0.03) yield grade, and increased (P < 0.10) time to consume 50 and 75% of daily intake relative to control steers. Our results suggest that feeding RAC for 35 d at 200 mg/(steer x d) provided optimal performance, and no effects on acid-base balance or variation in intake patterns of finishing steers were noted with RAC fed at 200 mg/(steer x d) over a 30-d period. PMID:17609477

  12. Chemical composition and acid-base properties of the surface of GaAs-CdS solid solutions

    Chemical composition and acid-base properties of the surfaces of GaAs-CdS solid solutions and the constituent binary compounds exposed to air, vacuum, CO, and NH3 were analyzed using mass spectrometry, IR spectrometry, isoelectric-point pH (pHiso) analysis, and mechanochemical methods. Powders and films were prepared from the solid solutions by isothermal diffusion and discrete vacuum evaporation, respectively. XRD and Raman analysis revealed that a solid solution has a sphalerite or wurtzite structure, depending on its composition. The initial surface of all the systems studied exhibited acidic properties: the pH value ranged from 4.9 to 6.45. The surfaces contained Lewis (electron accepting) and Bronsted (adsorbed H2O and CO2 molecules, OH- groups) sites. The acidity of the surface increased upon treatment with CO and decreased upon treatment with NH3. For all types of treatment, the concentration dependence of the acid-base properties of the surface exhibited an extremum. The strongest acidic sites were revealed on the surface of the (GaAs)0.95 (CdS)0.05 solid solution. The adsorption activity of this solution, a promising material for manufacturing gas sensors, was evaluated

  13. Spontaneous formation of biocompatible vesicles in aqueous mixtures of amino acid-based cationic surfactants and SDS/SDBS.

    Shome, Anshupriya; Kar, Tanmoy; Das, Prasanta K

    2011-02-01

    The spontaneous formation of vesicles by six amino acid-based cationic surfactants and two anionic surfactants (sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS)) is reported. The head-group structure of the cationic surfactants is minutely altered to understand their effect on vesicle formation. To establish the regulatory role of the aromatic group in self-aggregation, both aliphatic and aromatic side-chain-substituted amino acid-based cationic surfactants are used. The presence of aromaticity in any one of the constituents favors the formation of vesicles by cationic/anionic surfactant mixtures. The formation of vesicles is primarily dependent on the balance between the hydrophobicity and hydrophilicity of both cationic and anionic surfactants. Vesicle formation is characterized by surface tension, fluorescence anisotropy, transmission electron microscopy, dynamic light scattering, and phase diagrams. These vesicles are thermally stable up to 65 °C, determined by temperature-dependent fluorescence anisotropy. According to the MTT assay, these catanionic vesicles are nontoxic to NIH3T3 cells, thus indicating their wider applicability as delivery vehicles to cells. Among the six cationic surfactants examined, tryptophan- and tyrosine-based surfactants have the ability to reduce HAuCl(4) to gold nanoparticles (GNPs), which is utilized to obtain in-situ-synthesized GNPs entrapped in vesicles without the need for any external reducing agent. PMID:21275029

  14. Dentin bonding performance using Weibull statistics and evaluation of acid-base resistant zone formation of recently introduced adhesives.

    Guan, Rui; Takagaki, Tomohiro; Matsui, Naoko; Sato, Takaaki; Burrow, Michael F; Palamara, Joseph; Nikaido, Toru; Tagami, Junji

    2016-07-30

    Dentin bonding durability of recently introduced dental adhesives: Clearfil SE Bond 2 (SE2), Optibond XTR (XTR), and Scotchbond Universal (SBU) was investigated using Weibull analysis as well as analysis of the micromorphological features of the acid-base resistant zone (ABRZ) created for the adhesives. The bonding procedures of SBU were divided into three subgroups: self-etch (SBS), phosphoric acid (PA) etching on moist (SBM) or dry dentin (SBD). All groups were thermocycled for 0, 5,000 and 10,000 cycles followed by microtensile bond strength testing. Acid-base challenge was undertaken before SEM and TEM observations of the adhesive interface. The etch-and-rinse method with SBU (SBM and SBD) created inferior interfaces on the dentin surface which resulted in reduced bond durability. ABRZ formation was detected with the self-etch adhesive systems; SE2, XTR and SBS. In the PA etching protocols of SBM and SBD, a thick hybrid layer but no ABRZ was detected, which might affect dentin bond durability. PMID:27335136

  15. [Acid-base status in newborn calves during the first days of life considering different states of vitality].

    Herfen, K; Bostedt, H

    1999-06-01

    The aim of this study is to describe the differentiations of the acid-base status in bovine neonates during the first 96 hours of life. Due to the short intervals in the taking of blood samples, noticeable fluctuations in the acid-base status during the first minutes and hours of life of newborn calves were documented. Altogether, 25 matures and eutrophe calves of the DSB, DRB and DFV breeds were provided by the clinic for this study. Apart from an immediate post natum clinical interpretation of the vital signs in the neonates-using the APGAR-score-the pH value, current Base Excess and the CO2 pressure were simultaneously ascertained. Further continuous evaluation of the acid-base status was subsequently followed in the first phase of adaptation. For that alone, twelve blood samples were taken from the vena jugularis within the first 60 minutes after parturition. Until the end of the examination period on the fourth day of life, the tests amounted to 26 measurements altogether per experimentee. Due to the concrete results ascertained from the initial clinical and laboratory observations, the experimentees could be divided into distinct classes of vitality. The acid-base status of all the calves deteriorated during the first minutes of life, indicating that the pH value and Base Excess fall clearly under the initial level in all aspects of vitality directly post natum. On average the minimum pH values are reached between the third and 15th minute of life and remain between 0.019 and 0.096 below the initial values during this period. A varying rapid increase of the pH value follows, together with a balancing out of the Base difference. Despite isolated individual variations as the acid-base status develops, the lowering of the pH values in the first minutes of life is assessed as being a normal biological phenomenon. Deviations from this occur rarely (8%) and do not conform to the norm. The pH value stabilization in connection with this crucial early postnatal phase

  16. MHD equilibrium and stability of the spheromak

    Okabayashi, M.; Todd, A.M.M.

    1979-08-01

    The MHD stability of spheromak type equilibria from the classical spheromak configuration to the diffuse pinch limit are analyzed numerically. It is found that oblate configurations of ellipticity 0.5 have the optimum stability properties with regard to internal MHD modes and can be stabilized up to an engineering ..beta.. of 15% (defined with respect to the applied external field strength for equilibrium). Stability to global modes requires that a conducting shell surround the plasma. The location of the shell is dependent on geometry and the current profile, but realistic configurations that are stable to all ideal MHD modes have been found with the shell located at approx. 1.2 minor radii.

  17. Radiative equilibrium and escape of Pluto's atmosphere

    Erwin, Justin; Koskinen, Tommi T.; Yelle, Roger V.

    2015-11-01

    Observations of Pluto’s extend atmosphere by the New Horizons spacecraft motivate an update to our modeling effort on Pluto’s atmosphere. New Horizons observations have already improved our constraints on planet radius and surface pressure, which are key to modeling the atmospheric structure. We model the radiative conductive equilibrium in the lower atmosphere combined with the UV driven escape model of the upper atmosphere. The non-LTE radiative transfer model in the lower atmosphere include heating and cooling by CH4, CO, and HCN. The escape model of the upper atmosphere is updated to include diffusion and escape of each molecular component. These results will be used to aid in the analysis and better understanding of the full atmospheric structure.

  18. Equilibrium spin pulsars unite neutron star populations

    Ho, Wynn; Klus, Helen; Coe, Malcolm; Andersson, Nils

    2015-08-01

    We compare the large number of recent torque measurements of accreting pulsars with a high-mass companion to the standard model for how accretion affects the pulsar spin period. We find that many long spin period (P > 100 s) pulsars must possess either extremely weak (B 10^14 G) magnetic fields. We argue that the strong-field solution is more compelling, in which case these pulsars are near spin equilibrium. Our results provide evidence for a fundamental link between pulsars with the slowest spin periods and strong magnetic fields around high-mass companions and pulsars with the fastest spin periods and weak fields around low-mass companions. The strong magnetic fields also connect our pulsars to magnetars and strong-field isolated radio/X-ray pulsars. The strong field and old age of our sources suggests their magnetic field penetrates into the superconducting core of the neutron star.

  19. Non-equilibrium Thermodynamics of Spacetime

    Eling, C; Jacobson, T; Eling, Christopher; Guedens, Raf; Jacobson, Ted

    2006-01-01

    It has previously been shown that the Einstein equation can be derived from the requirement that the Clausius relation dS = dQ/T hold for all local acceleration horizons through each spacetime point, where dS is one quarter the horizon area change in Planck units, and dQ and T are the energy flux across the horizon and Unruh temperature seen by an accelerating observer just inside the horizon. Here we show that a curvature correction to the entropy that is polynomial in the Ricci scalar requires a non-equilibrium treatment. The corresponding field equation is derived from the entropy balance relation dS =dQ/T+dS_i, where dS_i is a bulk viscosity entropy production term that we determine by imposing energy-momentum conservation. Entropy production can also be included in pure Einstein theory by allowing for shear viscosity of the horizon.

  20. Extant mammal body masses suggest punctuated equilibrium.

    Mattila, Tiina M; Bokma, Folmer

    2008-10-01

    Is gradual microevolutionary change within species simultaneously the source of macroevolutionary differentiation between species? Since its first publication, Darwin's original idea that phenotypic differences between species develop gradually over time, as the accumulation of small selection-induced changes in successive generations has been challenged by palaeontologists claiming that, instead, new species quickly acquire their phenotypes to remain virtually unchanged until going extinct again. This controversy, widely known as the 'punctuated equilibrium' debate, remained unresolved, largely owing to the difficulty of distinguishing biological species from fossil remains. We analysed body masses of 2143 existing mammal species on a phylogeny comprising 4510 (i.e. nearly all) extant species to estimate rates of gradual (anagenetic) and speciational (cladogenetic) evolution. Our Bayesian estimates from mammals as well as separate sub-clades such as primates and carnivores suggest that gradual evolution is responsible for only a small part of body size variation between mammal species. PMID:18595835

  1. The Equilibrium Spreading Tension of Pulmonary Surfactant.

    Dagan, Maayan P; Hall, Stephen B

    2015-12-01

    Monomolecular films at an air/water interface coexist at the equilibrium spreading tension (γ(e)) with the bulk phase from which they form. For individual phospholipids, γ(e) is single-valued, and separates conditions at which hydrated vesicles adsorb from tensions at which overcompressed monolayers collapse. With pulmonary surfactant, isotherms show that monolayers compressed on the surface of bubbles coexist with the three-dimensional collapsed phase over a range of surface tensions. γ(e) therefore represents a range rather than a single value of surface tension. Between the upper and lower ends of this range, rates of collapse for spread and adsorbed films decrease substantially. Changes during adsorption across this narrow region of coexistence between the two- and three-dimensional structures at least partially explain how alveolar films of pulmonary surfactant become resistant to collapse. PMID:26583569

  2. The equilibrium leach testing of CAGR hulls

    Equilibrium leach tests were carried out on a laboratory scale in order to investigate the long-term performance of an intermediate level waste repository. The tests involved leaching fully active Commercial Advanced Gas-cooled Reactor (CAGR) hulls in the presence of crushed matrix and backfill materials. The matrix materials used were blast furnace slag (BFS)/ordinary Portland cement (OPC) and epoxide MS7531/MS7532, and the backfill materials were bentonite and pulverised fuel ash/ordinary Portland cement (PFA/OPC). Comparison of the long-lived radionuclide concentrations with the derived drinking water levels indicates that the performance of a repository under oxidising conditions would tend to be limited by the release of I-129 and Tc-99. (author)

  3. QUIL: a chemical equilibrium code. [HTGR

    Lunsford, J.L.

    1977-02-01

    A chemical equilibrium code QUIL is described, along with two support codes FENG and SURF. QUIL is designed to allow calculations on a wide range of chemical environments, which may include surface phases. QUIL was written specifically to calculate distributions associated with complex equilibria involving fission products in the primary coolant loop of the high-temperature gas-cooled reactor. QUIL depends upon an energy-data library called ELIB. This library is maintained by FENG and SURF. FENG enters into the library all reactions having standard free energies of reaction that are independent of concentration. SURF enters all surface reactions into ELIB. All three codes are interactive codes written to be used from a remote terminal, with paging control provided. Plotted output is also available.

  4. Oppositely charged colloids out of equilibrium

    Vissers, T.

    2010-11-01

    Colloids are particles with a size in the range of a few nanometers up to several micrometers. Similar to atomic and molecular systems, they can form gases, liquids, solids, gels and glasses. Colloids can be used as model systems because, unlike molecules, they are sufficiently large to be studied directly with light microscopy and move sufficiently slow to study their dynamics. In this thesis, we study binary systems of polymethylmethacrylate (PMMA) colloidal particles suspended in low-polar solvent mixtures. Since the ions can still partially dissociate, a surface charge builds up which causes electrostatic interactions between the colloids. By carefully tuning the conditions inside the suspension, we make two kinds of particles oppositely charged. To study our samples, we use Confocal Laser Scanning Microscopy (CLSM). The positively and negatively charged particles can be distinguished by a different fluorescent dye. Colloids constantly experience a random motion resulting from random kicks of surrounding solvent molecules. When the attractions between the oppositely charged particles are weak, the particles can attach and detach many times and explore a lot of possible configurations and the system can reach thermodynamic equilibrium. For example, colloidal ‘ionic’ crystals consisting of thousands to millions of particles can form under the right conditions. When the attractions are strong, the system can become kinetically trapped inside a gel-like state. We observe that when the interactions change again, crystals can even emerge again from this gel-like phase. By using local order parameters, we quantitatively study the crystallization of colloidal particles and identify growth defects inside the crystals. We also study the effect of gravity on the growth of ionic crystals by using a rotating stage. We find that sedimentation can completely inhibit crystal growth and plays an important role in crystallization from the gel-like state. The surface

  5. Punctuated equilibrium dynamics in human communications

    Peng, Dan; Wei, Zong-Wen; Wang, Bing-Hong

    2014-01-01

    A minimal model based on individual interactions is proposed to study the non-Poisson statistical properties of human behavior: individuals in the system interact with their neighbors, the probability of an individual acting correlates to its activity, and all individuals involved in action will change their activities randomly. The model creates rich non-Poisson spatial-temporal properties in the activities of individuals, in agreement with the patterns of human communication behaviors. Our findings provide insight into various human activities, embracing a range of realistic social interacting systems, particularly, intriguing bimodal phenomenons. This model bridges priority queues and punctuated equilibrium, and our modeling and analysis is likely to shed light on non-Poisson phenomena in many complex systems.

  6. Effect of impurity radiation on tokamak equilibrium

    The energy loss from a tokamak plasma due to the radiation from impurities is of great importance in the overall energy balance. Taking the temperature dependence of this loss for two impurities characteristic of those present in existing tokamak plasmas, the condition for radial power balance is derived. For the impurities considered (oxygen and iron) it is found that the radiation losses are concentrated in a thin outer layer of the plasma and the equilibrium condition places an upper limit on the plasma paraticle number density in this region. This limiting density scales with mean current density in the same manner as is experimentally observed for the peak number density of tokamak plasmas. The stability of such equilibria is also discussed. (author)

  7. The Fisher Market Game: Equilibrium and Welfare

    Branzei, Simina; Chen, Yiling; Deng, Xiaotie; Filos-Ratsikas, Aris; Frederiksen, Søren Kristoffer Stiil; Zhang, Jie

    The Fisher market model is one of the most fundamental resource allocation models in economics. In a Fisher market, the prices and allocations of goods are determined according to the preferences and budgets of buyers to clear the market. In a Fisher market game, however, buyers are strategic and...... report their preferences over goods; the market-clearing prices and allocations are then determined based on their reported preferences rather than their real preferences. We show that the Fisher market game always has a pure Nash equilibrium, for buyers with linear, Leontief, and Cobb-Douglas utility...... functions, which are three representative classes of utility functions in the important Constant Elasticity of Substitution (CES) family. Furthermore, to quantify the social efficiency, we prove Price of Anarchy bounds for the game when the utility functions of buyers fall into these three classes...

  8. Evolution and non-equilibrium physics

    Becker, Nikolaj; Sibani, Paolo

    2014-01-01

    We argue that the stochastic dynamics of interacting agents which replicate, mutate and die constitutes a non-equilibrium physical process akin to aging in complex materials. Specifically, our study uses extensive computer simulations of the Tangled Nature Model (TNM) of biological evolution...... to show that punctuated equilibria successively generated by the model's dynamics have increasing entropy and are separated by increasing entropic barriers. We further show that these states are organized in a hierarchy and that limiting the values of possible interactions to a finite interval leads...... to stationary fluctuations within a component of the latter. A coarse-grained description based on the temporal statistics of quakes, the events leading from one component of the hierarchy to the next, accounts for the logarithmic growth of the population and the decaying rate of change of macroscopic variables...

  9. Equilibrium stage model of the KALC process

    A computer program has been written to solve equilibrium stage models of the KALC process in as exact a manner as presently available data will permit using matrix algebra techniques. A correlation is presented which represents the thermodynamic properties of the multicomponent system CO2--Xe--O2--CO--N2--Kr at temperatures of -55 to 00C, pressures up to 70 atm, and over a range of concentrations of dissolved light gases likely to be of interest. The program has been tested for several possible system configurations with up to a total of 50 stages. A three-column configuration consisting of an absorber, a fractionator, and a stripper-rectifier column is used as an example

  10. Non-equilibrium in flowing atmospheric plasmas

    This thesis deals with the fundamental aspects of two different plasmas applied in technological processes. The first one is the cesium seeded argon plasma in a closed cycle Magnetohydrodynamic (MHD) generator, the second is the thermal argon plasma in a cascade arc with an imposed flow. In Chapter 2 the influence of non-equilibrium on the mass and energy balances of a plasma is worked out. The general theory presented there can be applied to both the plasma in an MHD generator and to the cascade arc with imposed flow. Introductions to these plasmas are given in the Chapters 3 and 6 respectively. These chapters are both followed by two chapters which treat the theoretical and the experimental investigations. The results are summarized in Chapter 9. (Auth.)

  11. Equilibrium statistical mechanics of lattice models

    Lavis, David A

    2015-01-01

    Most interesting and difficult problems in equilibrium statistical mechanics concern models which exhibit phase transitions. For graduate students and more experienced researchers this book provides an invaluable reference source of approximate and exact solutions for a comprehensive range of such models. Part I contains background material on classical thermodynamics and statistical mechanics, together with a classification and survey of lattice models. The geometry of phase transitions is described and scaling theory is used to introduce critical exponents and scaling laws. An introduction is given to finite-size scaling, conformal invariance and Schramm—Loewner evolution. Part II contains accounts of classical mean-field methods. The parallels between Landau expansions and catastrophe theory are discussed and Ginzburg—Landau theory is introduced. The extension of mean-field theory to higher-orders is explored using the Kikuchi—Hijmans—De Boer hierarchy of approximations. In Part III the use of alge...

  12. Measured MHD equilibrium in Alcator C

    A method of processing data from a set of partial Rogowski loops is developed to study the MHD equilibrium in Alcator C. Time dependent poloidal fields in the vicinity of the plasma are calculated from measured currents, with field penetration effects being accounted for. Fields from eddy currents induced by the plasma in the tokamak structure are estimated as well. Each of the set of twelve B/sub θ/ measurements can then be separated into a component from the plasma current and a component from currents external to the pickup loops. Harmonic solutions to Maxwell's equations in toroidal coordinates are fit to these measurements in order to infer the fields everywhere in the vacuum region surrounding the plasma. Using this diagnostic, plasma current, position, shape, and the Shafranov term Λ = β/sub p/ + l/sub i//2 - 1 may be computed, and systematic studies of these plasma parameters are undertaken for Alcator C plasmas

  13. Punctuated equilibrium dynamics in human communications

    Peng, Dan; Han, Xiao-Pu; Wei, Zong-Wen; Wang, Bing-Hong

    2015-10-01

    A minimal model based on network incorporating individual interactions is proposed to study the non-Poisson statistical properties of human behavior: individuals in system interact with their neighbors, the probability of an individual acting correlates to its activity, and all the individuals involved in action will change their activities randomly. The model reproduces varieties of spatial-temporal patterns observed in empirical studies of human daily communications, providing insight into various human activities and embracing a range of realistic social interacting systems, particularly, intriguing bimodal phenomenon. This model bridges priority queueing theory and punctuated equilibrium dynamics, and our modeling and analysis is likely to shed light on non-Poisson phenomena in many complex systems.

  14. Chemical equilibrium analysis of dry hydrogen combustion

    The present work is based on a thermo-chemical equilibrium model for studying the effect of combustion of hydrogen during postulated accident scenarios in nuclear reactor containments. This model is based on the method of element potentials which seeks to minimize the free energy of the system. The condition on internal energy balance is imposed as a constraint during the minimization process. Another simplified model purely based on the internal energy balance has also been implemented to investigate the isolated impact of free energy and the conditions under which it becomes dominant. The two models have been used to extract final pressures for a wide range of initial conditions and mixture compositions that are typically found during accident scenarios. In the absence of hydrogen combustion experimental data, such models will become important for laying down a first estimate on the possible outcomes. (author)

  15. Equilibrium Configurations of Cantilever under Terminal Loads

    Batista, Milan

    2013-01-01

    The paper provides an exact analytical solution for equilibrium configurations of cantilever rod subject to inclined force and torque acting on its free end. The solution is given in terms of Jacobi elliptical functions and illustrated by several numerical examples and several graphical presentations of shapes of deformed cantilever. Possible forms of cantilever underlying elastica are discussed in details and various simple formulas are given for calculation of characteristic dimensions of elastica. For the case when cantilever is subject only to applied force four load conditions are discussed: follower load problem, load determination problem, conservative load problem and rotational load problem. For all the cases the formulas or effective procedure for solution is given.

  16. Nash equilibrium and multi criterion aerodynamic optimization

    Tang, Zhili; Zhang, Lianhe

    2016-06-01

    Game theory and its particular Nash Equilibrium (NE) are gaining importance in solving Multi Criterion Optimization (MCO) in engineering problems over the past decade. The solution of a MCO problem can be viewed as a NE under the concept of competitive games. This paper surveyed/proposed four efficient algorithms for calculating a NE of a MCO problem. Existence and equivalence of the solution are analyzed and proved in the paper based on fixed point theorem. Specific virtual symmetric Nash game is also presented to set up an optimization strategy for single objective optimization problems. Two numerical examples are presented to verify proposed algorithms. One is mathematical functions' optimization to illustrate detailed numerical procedures of algorithms, the other is aerodynamic drag reduction of civil transport wing fuselage configuration by using virtual game. The successful application validates efficiency of algorithms in solving complex aerodynamic optimization problem.

  17. Open quantum systems far from equilibrium

    Schaller, Gernot

    2014-01-01

    This monograph provides graduate students and also professional researchers aiming to understand the dynamics of open quantum systems with a valuable and self-contained toolbox. Special focus is laid on the link between microscopic models and the resulting open-system dynamics. This includes how to derive the celebrated Lindblad master equation without applying the rotating wave approximation. As typical representatives for non-equilibrium configurations it treats systems coupled to multiple reservoirs (including the description of quantum transport), driven systems, and feedback-controlled quantum systems. Each method is illustrated with easy-to-follow examples from recent research. Exercises and short summaries at the end of every chapter enable the reader to approach the frontiers of current research quickly and make the book useful for quick reference.

  18. The anelastic equilibrium tide in exoplanetary systems

    Remus, F; Zahn, J -P; Lainey, V

    2012-01-01

    Earth-like planets have anelastic mantles, whereas giant planets may have anelastic cores. As for the fluid parts of a body, the tidal dissipation of such solid regions, gravitationally perturbed by a companion body, highly depends on its internal friction, and thus on its internal structure. Therefore, modelling this kind of interaction presents a high interest to provide constraints on planet interiors, whose properties are still quite uncertain. Here, we examine the equilibrium tide in the solid central region of a planet, taking into account the presence of a fluid envelope. We first present the equations governing the problem, and show how to obtain the different Love numbers that describe its deformation. We discuss how the quality factor Q depends on the rheological parameters, and the size of the core. Taking plausible values for the anelastic parameters, and examinig the frequency-dependence of the solid dissipation, we show how this mechanism may compete with the dissipation in fluid layers, when ap...

  19. The market equilibrium of OPEC's pricing mechanism

    At least twice a year, oil ministers of the Organization of the Petroleum Exporting Countries (OPEC) meet in Vienna or Geneva to adjust the group's output ceiling to eliminate discrepancies between the market price and the target price. If the market imbalances are persistent, then the target price is also adjusted. Often, OPEC's members differ in their assessment of future market demand for their oil and, thus, present different views on the need to adjust the output celing and the target price. During periods of downward pressures on oil prices, the high absorbers of capital (i.e., oil revenues) prefer a speedy downward adjustment to the celing, while the low absorbers are slow to react. However, in the event of tightening markets, the low absorbers usually respond by exceeding their quotas before agreeing on a ceiling adjustment. Therefore, OPEC nations have different desirable speeds of adjustment. This paper specifies and examines the stability of OPEC's pricing mechanism. It presents a strategy which would enable the organization to achieve a target price-based market equilibrium with increased rapidity through the appropriate manipulation of the speed of output ceiling adjustment. This strategy is applied using data on market and target prices, actual output, and output ceilings for the first quarter of 1991. The main finding is that, given the target price, OPEC's equilibrium market demand is significantly lower than the assigned output ceiling. Production should have been reduced by at least 3 million barrels a day for OPEC to realize the $21 per barrel target price in the first quarter of 1991. Seasonal factors can cause slight variations in this output but would not bring out compatibility between the target price and the output ceiling within a reasonable period of time unless OPEC follows an activist policy of output adjustment. 3 figs., 1 tab

  20. Statistical physics of shear flow: a non-equilibrium problem

    Evans, R. M. L.

    2010-09-01

    Complex fluids are easily and reproducibly driven into non-equilibrium steady states by the action of shear flow. The statistics of the microstructure of non-equilibrium fluids is important to the material properties of every complex fluid that flows, e.g. axle grease on a rotating bearing; blood circulating in capillaries; molten plastic flowing into a mould; the non-equilibrium onion phase of amphiphiles used for drug delivery; the list is endless. Such states are as diverse and interesting as equilibrium states, but are not governed by the same statistics as equilibrium materials. I review some recently discovered principles governing the probabilities of various types of molecular re-arrangements taking place within a sheared fluid. As well as providing new foundations for the study of non-equilibrium matter, the principles are applied to some simple models of particles interacting under flow, showing that the theory exhibits physically convincing behaviour.

  1. Chemical Equilibrium as Balance of the Thermodynamic Forces

    Zilbergleyt, B

    2004-01-01

    The article sets forth comprehensive basics of thermodynamics of chemical equilibrium as balance of the thermodynamic forces. Based on the linear equations of irreversible thermodynamics, De Donder definition of the thermodynamic force, and Le Chatelier's principle, new thermodynamics of chemical equilibrium offers an explicit account for multiple chemical interactions within the system. Basic relations between energetic characteristics of chemical transformations and reaction extents are based on the idea of chemical equilibrium as balance between internal and external thermodynamic forces, which is presented in the form of a logistic equation, containing only one new parameter. Solutions to the basic equation define the domain of states of the chemical system, from true equilibrium to true chaos. The new theory is derived exclusively from the currently recognized ideas and covers equilibrium thermodynamics as well as non-equilibrium thermodynamics in a unique concept.

  2. Critical dynamics a field theory approach to equilibrium and non-equilibrium scaling behavior

    Täuber, Uwe C

    2014-01-01

    Introducing a unified framework for describing and understanding complex interacting systems common in physics, chemistry, biology, ecology, and the social sciences, this comprehensive overview of dynamic critical phenomena covers the description of systems at thermal equilibrium, quantum systems, and non-equilibrium systems. Powerful mathematical techniques for dealing with complex dynamic systems are carefully introduced, including field-theoretic tools and the perturbative dynamical renormalization group approach, rapidly building up a mathematical toolbox of relevant skills. Heuristic and qualitative arguments outlining the essential theory behind each type of system are introduced at the start of each chapter, alongside real-world numerical and experimental data, firmly linking new mathematical techniques to their practical applications. Each chapter is supported by carefully tailored problems for solution, and comprehensive suggestions for further reading, making this an excellent introduction to critic...

  3. Issues in current User Equilibrium models and introduction of the Restricted Stochastic User Equilibrium conditions

    Rasmussen, Thomas Kjær; Watling, David P.; Prato, Carlo Giacomo;

    -off is strictly enforced: in a time-only model, if the current equilibrium travel time is 15.3 minutes, then adding a route with travel time of 15.4 minutes will have no impact on routing behaviour, whereas in practice (because of uncertainty, variability and unobserved attributes) the new route is...... trip being made. This issue is further complicated by the fact that typically only a sub-set of possible routes will be identified in numerical algorithms solving for SUE. In the current study, we present new alternative forms of SUE conditions that permit unused alternatives, accommodate behaviour on...... used alternatives according to Random Utility Theory, and are generic in the sense that may be applied to any SUE model and any solution method. We define this new set of conditions as the Restricted Stochastic User Equilibrium (RSUE) conditions. Then, we focus on solution algorithms and we argue that...

  4. Non-Equilibrium Thermodynamics in Conformal Field Theory

    Hollands, Stephan

    2016-01-01

    We present a model independent, operator algebraic approach to non-equilibrium quantum thermodynamics within the framework of two-dimensional Conformal Field Theory. Two infinite reservoirs in equilibrium at their own temperatures and chemical potentials are put in contact through a defect line, possibly by inserting a probe. As time evolves, the composite system then approaches a non-equilibrium steady state that we describe. In particular, we re-obtain recent formulas of Bernard and Doyon.

  5. Analysis of the chemical equilibrium of combustion at constant volume

    Marius BREBENEL

    2014-01-01

    Determining the composition of a mixture of combustion gases at a given temperature is based on chemical equilibrium, when the equilibrium constants are calculated on the assumption of constant pressure and temperature. In this paper, an analysis of changes occurring when combustion takes place at constant volume is presented, deriving a specific formula of the equilibrium constant. The simple reaction of carbon combustion in pure oxygen in both cases (constant pressure and constant ...

  6. Equilibrium and thermodynamics of azo dyes biosorption onto Spirulina platensis

    G. L. Dotto; M. L. G. Vieira; V. M. Esquerdo; L. A. A. PINTO

    2013-01-01

    The equilibrium and thermodynamics of azo dye (tartrazine and allura red) biosorption onto Spirulina platensis biomass were investigated. The equilibrium curves were obtained at 298, 308, 318 and 328 K, and four isotherm models were fitted the experimental data. Biosorption thermodynamic parameters (ΔG, ΔH and ΔS) were estimated. The results showed that the biosorption was favored by a temperature decrease. For both dyes, the Sips model was the best to represent the equilibrium...

  7. Slope Stability Analysis Using Limit Equilibrium Method in Nonlinear Criterion

    Hang Lin; Wenwen Zhong; Wei Xiong; Wenyu Tang

    2014-01-01

    In slope stability analysis, the limit equilibrium method is usually used to calculate the safety factor of slope based on Mohr-Coulomb criterion. However, Mohr-Coulomb criterion is restricted to the description of rock mass. To overcome its shortcomings, this paper combined Hoek-Brown criterion and limit equilibrium method and proposed an equation for calculating the safety factor of slope with limit equilibrium method in Hoek-Brown criterion through equivalent cohesive strength and the fric...

  8. Existence of a competitive equilibrium when all goods are indivisible

    Michael Florig; Jorge Rivera

    2015-01-01

    We study a production economy where all consumption goods are indivisible at the individual level but perfectly divisible at the overall economy level. In order to facilitate the exchange, we introduce a perfectly divisible parameter that does not enter into consumer preferences (fiat money). When consumption goods are indivisible, a Walras equilibrium does not necessarily exist. Hence, we introduce a new concept of competitive equilibrium for the economy (called rationing equilibrium), and t...

  9. PEMAHAMAN DASAR ANALISIS MODEL COMPUTABLE GENERAL EQUILIBRIUM (CGE)

    Mardiyah Hayati

    2013-01-01

    Simple paper about basic understanding of computable general equilibrium aimed to give basic understanding about CGE. It consist of history of CGE, assumption of CGE model, excess and lack of CGE model, and creation of simple CGE model for closed economy. CGE model is suitable to be used for seeing impact of new policy implementation. It is because CGE model use general equilibrium in which this theory of general equilibrium explaining about inter-relation among markets in the economy system....

  10. Game Theory in Social Media with Quantal Response Equilibrium

    Elmgren, Rasmus; Blomquist, Eric

    2015-01-01

    This paper examines the possibility to construct a Game Theory model to describe Social Media with a Quantal Response Equilibrium. It is based on a literature study. The paper is influenced by "A Game-theoretic Model of Attention in Social Networks" written by Goel and Ronaghi but creates a more realistic model by replacing their Nash Equilibrium with a Quantal Response Equilibrium. Such model is constructed in the Result section and elaborated further in the Discussion. This paper also discu...

  11. Equilibrium time correlation functions and the dynamics of fluctuations

    Equilibrium time correlation functions are of great importance because they probe the equilibrium dynamical response to external perturbations. We discuss the properties of time correlation functions for several systems that are simple enough to illustrate the calculational steps involved. The discussion underscores the need for avoiding language which misleadingly suggests that thermal equilibrium is associated with a quiescent or moribund state of the system. (c) 1999 American Association of Physics Teachers

  12. The Subjective Game Form and Institutional Evolution as Punctuated Equilibrium

    Masahiko Aoki

    1998-01-01

    September 1998 The major purpose of this lecture is to provide a conceptual framework for analyzing the mechanism of institutional evolution as "punctuated equilibrium." Section 1 introduces reasons why an equilibrium view of institutions may be appropriate. Section 2 introduces a simple apparatus, called the COSE box, to represent the structure of the game. Section 3 then provides an equilibrium-related conception of institutions satisfying the four observed features: summary representation,...

  13. Relative profit maximization and Bertrand equilibrium with convex cost functions

    Satoh, Atsuhiro; Tanaka, Yasuhito

    2014-01-01

    The authors study pure strategy Bertrand equilibria in a duopoly in which two firms produce a homogeneous good with convex cost functions, and they seek to maximize the weighted sum of their absolute and relative profits. They show that there exists a range of the equilibrium price in duopolistic equilibria. This range of the equilibrium price is narrower and lower than the range of the equilibrium price in duopolistic equilibria under pure absolute profit maximization, and the larger the wei...

  14. Determination of gross plasma equilibrium from magnetic multipoles

    A new approximate technique to determine the gross plasma equilibrium parameters, major radius, minor radius, elongation and triangularity for an up-down symmetric plasma is developed. It is based on a multipole representation of the externally applied poloidal magnetic field, relating specific terms to the equilibrium parameters. The technique shows reasonable agreement with free boundary MHD equilibrium results. The method is useful in dynamic simulation and control studies

  15. Non-equilibrium and band tailing in organic conductors

    A T Oza; P C Vinodkumar; R G Patel

    2003-03-01

    The concept of band tailing with focal point and width of the tail from IR absorption spectra of different organic conductors is found valid even for thermal and elastic changes. The experimental situations like change of solvents, method of preparation, applied pressure and pressure cycle apart from compositions is analyzed within the framework of tailing of states. Non-equilibrium due to coupling between applied energy and free electrons can be responsible for the exponential relaxation from non-equilibrium to equilibrium.

  16. The Godless Religion: Economics, Equilibrium, and the Copernican Revolution

    Freeman, Alan

    2001-01-01

    The paper argues that a formal, and fruitful, historical analogy can be drawn between economics and a religious hierarchy, most notably the mediaeval Catholic church. This idea was fully developed in Freeman (2007), ‘Heavens Above: what equilibrium means for economics’, in Mosini, V (ed) (2007) Equilibrium in Economics: Scope and Limits. London: Routledge ISBN 0415391377 It was entitled ‘Heavens above: what equilibrium means for economics’, and appeared on pp240-260. This paper was published...

  17. Directed Search for Equilibrium Wage-Tenure Contracts

    Shouyong Shi

    2006-01-01

    I analyze the equilibrium in a labor market where firms offer wage-tenure contracts to direct the search of employed and unemployed workers. Each applicant observes all offers and there is no coordination among individuals. Workers' applications (as well as firms' recruiting decisions) are optimal. This optimality requires the equilibrium to be formulated differently from the that in the literature of undirected search. I provide such a formulation and show that the equilibrium exists. In the...

  18. Phase Fluctuations and Non-Equilibrium Josephson Effect

    Narozhny, B. N.; Aleiner, I. L.

    1999-01-01

    We consider a diffusive S-N-S junction with electrons in the normal layer driven out of equilibrium by external bias. We show that, the non-equilibrium fluctuations of the electron density in the normal layer cause the fluctuations of the phase of the order parameter in the S-layers. As a result, the magnitude of the Josephson current in the non-equilibrium junction is significantly supressed relative to its mean field value.

  19. Equilibrium Policy Experiments and the Evaluation of Social Programs

    Lise, Jeremy; Seitz, Shannon; Smith, Jeffrey A.

    2004-01-01

    This paper makes three contributions to the literature on program evaluation. First, we construct a model that is well-suited to conduct equilibrium policy experiments and we illustrate effectiveness of general equilibrium models as tools for the evaluation of social programs. Second, we demonstrate the usefulness of social experiments as tools to evaluate models. In this respect, our paper serves as the equilibrium analogue to LaLonde (1986) and others, where experiments are used as a benchm...

  20. Competitive Equilibrium in the Credit Market under Asymmetric Information

    David Besanko; Anjan V. Thakor

    2004-01-01

    We study a competitive credit market equilibrium in which all agents are risk neutral and lenders a priori unaware of borrowers' default probabilities. Admissible credit contracts are characterized by the credit granting probability, the loan quantity, the loan interest rate and the collateral required. The principal result is that in equilibrium lower risk borrowers pay higher interest rates than higher risk borrowers; moreover, the lower risk borrowers get more credit in equilibrium than th...