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Magnesium-Uranium Alloy System

Description: Analytical, x-ray, thermal, and metallographic data have been obtained in the study of the magnesium-uranium system, and a proposed phase diagram has been constructed.
Date: 1954
Creator: Tracy, George A.; Chiotti, P. & Wilhelm, Harley A.
Partner: UNT Libraries Government Documents Department

Hadronic Correlations and Fluctuations

Description: We will provide a review of some of the physics which can be addressed by studying fluctuations and correlations in heavy ion collisions. We will discuss Lattice QCD results on fluctuations and correlations and will put them into context with observables which have been measured in heavy-ion collisions. Special attention will be given to the QCD critical point and the first order co-existence region, and we will discuss how the measurement of fluctuations and correlations can help in an experimental search for non-trivial structures in the QCD phase diagram.
Date: October 9, 2008
Creator: Koch, Volker
Partner: UNT Libraries Government Documents Department

The f-spin physics of rare-earth iron pnictides: influence of d-electron antiferromagnetic order on heavy fermion phase diagram

Description: Some of the high {Tc} iron pnictides contain rare-earth elements, raising the question of how the existence and tunability of a d-electron antiferromagnetic order influences the heavy fermion behavior of the f-moments. With CeOFeP and CeOFeAs in mind as prototypes, we derive an extended Anderson lattice model appropriate for these quaternary systems. We show that the Kondo screening of the f-moments are efficiently suppressed by the d-electron ordering. We also argue that, inside the d-electron ordered state (as in CeOFeAs), the f-moments provide a rare realization of a quantum frustrated magnet with competing J{sub 1}-J{sub 2}-J{sub 3} interactions in an effective square lattice. Implications ofr the heavy fermion physics in broader contexts are also discussed.
Date: January 1, 2009
Creator: Zhu, Jian-xin; Dai, Jianhui & Si, Qimiao
Partner: UNT Libraries Government Documents Department

Effect of salt identity on the phase diagram for a globularprotein in aqueous electrolyte solution

Description: Monte Carlo simulations are used to establish the potential of mean force between two globular proteins in an aqueous electrolyte solution. This potential includes nonelectrostatic contributions arising from dispersion forces first, between the globular proteins, and second, between ions in solution and between each ion and the globular protein. These latter contributions are missing from standard models. The potential of mean force, obtained from simulation, is fitted to an analytic equation. Using our analytic potential of mean force and Barker-Henderson perturbation theory, we obtain phase diagrams for lysozyme solutions that include stable and metastable fluid-fluid and solid-fluid phases when the electrolyte is 0.2 M NaSCN or NaI or NaCl. The nature of the electrolyte has a significant effect on the phase diagram.
Date: February 22, 2006
Creator: Bostrom, Mathias; Tavares, Frederico W.; Ninham, Barry W. & Prausnitz, John M.
Partner: UNT Libraries Government Documents Department

Estimated D$sub 2$-DT-T$sub 2$ phase diagram in the three-phase region

Description: A composite of experimental eH$sub 2$-D$sub 2$ phase-diagram data at the three-phase line is assembled from the literature. The phase diagram is a smooth cigar shape without a eutectic point, indicating complete miscibility of liquid and solid phases. Additional data are used to estimate the D$sub 2$-T$sub 2$, D$sub 2$-DT, and DT-T$sub 2$ binary phase diagrams. These are assembled into the ternary D$sub 2$-DT-T$sub 2$ phase diagram. A surface representing the chemical equilibrium of the three species is added to the phase diagram. At chemical equilibrium, it is estimated that 50-50 liquid D-T at 19.7 K is in equilibrium with 42 mole percent T vapor and 54 percent T solid. Infrared spectroscopy is suggested as a means of component analysis of liquid and solid mixtures. (auth)
Date: August 26, 1975
Creator: Souers, P.C.; Hickman, R.G. & Tsugawa, R.T.
Partner: UNT Libraries Government Documents Department

Nature of the Triple Point in Chromium Alloys: Mode-Softening of the Incommensurate Spin Density Wave

Description: The magnetic stiffness parameter, A2, associated with the critical fluctuations in the paramagnetic phase close to the incommensurate spin-density-wave (SDW) transition of a Cr+0.18at.%Re single crystal, when compared with that of in pure chromium and dilute alloys of vanadium in chromium, indicates that the singularity responsible for the onset of the commensurate SDW phase occurs when A2 approaches zero at a finite value of the incommensurability parameter, delta 0.017 rlu, instead of zero as usually assumed. The mode of the incommensurate SDW softens as delta approaches this critical value with rhenium doping, and conversely hardens as delta increases when vanadium is added to chromium. Also, the amplitude of the critical scattering increases as delta approaches its end point, by a factor of about two going from 0.2 and 0.5at.%V to pure chromium, and by another factor near two in going from pure Cr to Cr+0.18at.%Re.
Date: December 31, 1997
Creator: Noakes, D.R.; Fawcett, E.; Sternlieb, B.L.; Shirane, G. & Jankowska, J.
Partner: UNT Libraries Government Documents Department

AN ANALOGUE SOLUTION OF A REACTOR PERTURBATION INITIATED BY A METALLURGICAL PHASE TRANSFORMATION OF THE FUEL

Description: The analysis of a reactor model that is thermally nonlinear is presented. The significant sources of feadback in the closed-loop model ane dilatational changes of the fuel due to axial expansion caused by temperature and metallurgical phase changes. Ths dynamics of this phenomenon has been represented on the Pace electronic analog com puter. The model was subjected to unusually large inputs of sinusoidal power and did not show any drastic tendencies toward being unstable. (auth)
Date: January 1, 1961
Creator: Bryant, L.T.; Carter, J.C. & Janicke, M.J.
Partner: UNT Libraries Government Documents Department

Construction of the Magnetic Phase Diagram of FeMn/Ni/Cu(001) Using Photoemission Electron Microscopy

Description: Single crystalline FeMn/Ni bilayer was epitaxially grown on Cu(001) substrate and investigated by photoemission electron microscopy (PEEM). The FeMn and Ni films were grown into two cross wedges to facilitate an independent control of the FeMn (0-20 ML) and Ni (0-20 ML) film thicknesses. The Ni magnetic phases were determined by Ni domain images as a function of the Ni thickness (d{sub Ni}) and the FeMn thickness (d{sub FeMn}). The result shows that as the Ni thickness increases, the Ni film undergoes a paramagnetic-to-ferromagnetic state transition at a critical thickness of d{sub FM} and an in-plane to out-of-plane spin reorientation transition at a thicker thickness d{sub SRT}. The phase diagram shows that both d{sub FM} and d{sub SRT} increase as the FeMn film establishes its antiferromagnetic order.
Date: January 4, 2011
Creator: Wu, J.; Scholl, A.; Arenholz, E.; Hwang, C. & Qiu, Z. Q.
Partner: UNT Libraries Government Documents Department

Three Frontiers in the Thermodynamics of Protein Solutions

Description: Three examples illustrate the versatility and usefulness of biothermodynamics. The first example concerns calculation of a phase diagram for aqueous lysozyme with a new potential of mean force that takes the Hofmeister effect into account; such calculations may be useful for design of a separation process where addition of a salt to an aqueous protein mixture precipitates a target protein. The second example concerns thermodynamic studies to elucidate the effect of an organic cosolvent on the mechanism of crystallizing aqueous insulin. The final example concerns a thermodynamic contribution to mitigating the AIDS epidemic; it indicates how isothermal-titration-calorimetry studies are helpful for choosing an optimum inhibitor that is effective not only for the wild-type HIV protease but also for at least some of its mutants.
Date: August 30, 2006
Creator: Prausnitz, John & Hagar, Loddie
Partner: UNT Libraries Government Documents Department

2011 Superconductivity Gordon Research Conference (June 5-10, 2011, Waterville Valley Resort, Waterville Valley, New Hampshire)

Description: The 2011 Gordon Research Conference on Superconductivity will commemorate the 100th anniversary of the discovery of superconductivity by providing a forum for discussion of the latest experimental and theoretical advances in this field. The conference will bring together experts to address the current challenges in understanding correlated superconductors - from cuprates and pnictides to heavy fermion superconductors. The fundamental mechanisms of superconducting pairing, the underlying explanations for thermodynamic phase diagrams including potential importance of competing phases, the correspondence between these phenomena, and the transport and spectroscopic properties of these materials will be among the themes of the conference. We will also discuss the feasibility of using lessons learned from the study of known superconductors as a guide to the future discovery of novel and higher temperature superconductors. Speakers will be strongly encouraged to present new, unpublished work, which will ensure that discussions evoke and explore new research directions. The participation of young scientists at the graduate student or post-doctoral level will be encouraged by the offering of selected presentations, focused discussions with invited speakers, and poster sessions. In addition, the organizers have earmarked funds to facilitate attendance of members of groups underrepresented in science and engineering.
Date: June 10, 2011
Creator: Yazdani, Ali
Partner: UNT Libraries Government Documents Department

RHIC CRITICAL POINT SEARCH: ASSESSING STARs CAPABILITIES.

Description: In this report we discuss the capabilities and limitations of the STAR detector to search for signatures of the QCD critical point in a low energy scan at RHIC. We find that a RHIC low energy scan will cover a broad region of interest in the nuclear matter phase diagram and that the STAR detector--a detector designed to measure the quantities that will be of interest in this search--will provide new observables and improve on previous measurements in this energy range.
Date: July 3, 2006
Creator: SORENSEN,P.
Partner: UNT Libraries Government Documents Department

RHIC RF Harmonic Numbers for Low Energy Operations

Description: There have been several test runs of RHIC operations to explore the feasibility of luminosity production at low energies. There is considerable international interest in the possible existence of a QCD phase diagram critical point in the RHIC gold-gold collision energy range of {radical}s{sub NN} = 5-50 GeV[l, 2, 3]. This paper reviews the RF harmonic number constraints for RHIC gold-gold collisions in this energy range, and concludes that optimal simultaneous collisions at both experiments are only feasible when the harmonic number is divisible by 9.
Date: May 1, 2008
Creator: Satogata,T.
Partner: UNT Libraries Government Documents Department

Quarkyonic Matter and the Phase Diagram of QCD

Description: Quarkyonic matter is a new phase of QCD at finite temperature and density which is distinct from the confined and de-confined phases. Its existence is unambiguously argued in the large numbers of colors limit, N{sub c} {yields} {infinity}, of QCD. Hints of its existence for QCD, N{sub c} = 3, are shown in lattice Monte-Carlo data and in heavy ion experiments.
Date: May 15, 2008
Creator: McLerran,L.
Partner: UNT Libraries Government Documents Department

Feasibility of Electron Cooling for Low-Energy RHIC Operation

Description: A concrete interest in running RHIC at low energies in a range of 2.5-25 GeV/nucleon total energy of a single beam has recently emerged. Providing collisions in this energy range, which in the RHIC case is termed 'low-energy' operation, will help to answer one of the key questions in the field of QCD about existence and location of a critical point on the QCD phase diagram. However, luminosity projections are relatively low for the lowest energy points of interest. Luminosity improvement can be provided with electron cooling applied directly in RHIC at low energies. This report summarizes the expected luminosity improvement with electron cooling, possible technical approaches and various limitations.
Date: April 1, 2008
Creator: Fedotov,A.; Ben-Zvi, I.; Chang, X.; Kayran, D.; Litvinenko, V.; Pozdeyev, E. et al.
Partner: UNT Libraries Government Documents Department

Modelling Thermodynamics of Alloys for Fusion Application

Description: This research has two main objectives: (1) On one side is the development of computational tools to evaluate alloy properties, using the information contained in thermodynamic functions to improve the ability of classic potentials to account for complex alloy behavior. (2) On the other hand, to apply the tools so developed to predict properties of alloys under irradiation. Atomistic simulations of alloys at the empirical level face the challenge of correctly modeling basic thermodynamic properties. In this work we develop a methodology to generalize many-body classic potentials to incorporate complex formation energy curves. Application to Fe-Cr allows us to predict the implications of the ab initio results of formation energy on the phase diagram of this alloy.
Date: January 26, 2006
Creator: Caro, A; Sadigh, B; Turchi, P A; Caro, M; Lopasso, E & Crowson, D
Partner: UNT Libraries Government Documents Department

MODELLING THERMODYNAMICS OF ALLOYS FOR FUSION APPLICATION . Semi annual report for the Fusion Program

Description: This research has two main objectives: (1) The development of computational tools to evaluate alloy properties, using the information contained in thermodynamic functions. We aim at improving the ability of classical potentials to account for complex alloy behavior; and (2) The application of these tools to predict properties of alloys under irradiation. Atomistic simulations of alloys at the empirical level face the challenge of correctly modeling basic thermodynamic properties. In the periods reported previously we develop a methodology to generalize many-body classic potentials to incorporate complex formation energy curves. Application to Fe-Cr allows us to predict the implications of the ab initio results of formation energy on the phase diagram of this alloy and to get a detailed insight into the processes leading to precipitation of {alpha}{prime} phase under irradiation. In particular in this period we report on the consequences of the negative heat of formation at low Cr composition on the short range order SRO existing in the {alpha} phase. We elaborate a simple description of SRO on a two phase alloy and compare the predictions with experiments. We provide a key to rationalize a diversity of experiments on SRO versus annealing time or irradiation dose.
Date: July 31, 2007
Creator: Caro, J A
Partner: UNT Libraries Government Documents Department