A spectroscopic hike in the U–O phase diagram

The U–O phase diagram is of paramount interest for nuclear-related applications and has therefore been extensively studied. Experimental data have been gathered to feed the thermodynamic calculations and achieve an optimization of the U–O system modelling. Although considered as well established, a critical assessment of this large body of experimental data is necessary, especially in light of the recent development of new techniques applicable to actinide materials. Here we show how in situ X-ray absorption near-edge structure (XANES) is suitable and relevant for phase diagram determination. New experimental data points have been collected using this method and discussed in regard to the available data. Comparing our experimental data with thermodynamic calculations, we observe that the current version of the U–O phase diagram misses some experimental data in specific domains. This lack of experimental data generates inaccuracy in the model, which can be overcome using in situ XANES. Indeed, as shown in the paper, this method is suitable for collecting experimental data in non-ambient conditions and for multiphasic systems.

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Calculated phase diagrams for activated low pressure diamond growth from C–H, C–O, and C–H–O systems

Journal of Materials Research ◽

10.1557/jmr.1997.0426 ◽

1997 ◽

Vol 12 (12) ◽

pp. 3250-3253 ◽

Cited By ~ 19

Author(s):

Ji-Tao Wang ◽

Yong-Zhong Wan ◽

David Wei Zhang ◽

Zhi-Jie Liu ◽

Zhong-Qiang Huang

Keyword(s):

Experimental Data ◽

Phase Diagram ◽

Phase Diagrams ◽

Linear Combination ◽

Three Dimensional ◽

Low Pressure ◽

Diamond Growth ◽

Growth Region ◽

Calculated Phase ◽

O Phase

Three-dimensional temperature (T)–pressure (P)–composition (X) phase diagrams of binary carbon-hydrogen (C–H) and carbon-oxygen (C–O) systems for activated low pressure diamond growth have been calculated. Based on an approximation of linear combination between C–H and C–O systems, a projective ternary carbonhydrogen-oxygen (C–H–O) phase diagram has also been obtained. There is always a diamond growth region in each of these phase diagrams. Once a supply of external activating energy stops, the diamond growth region will not exist. Nearly all of the reliable experimental data reported in the literature drop into the possible diamond growth region of the calculated projective ternary C–H–O phase diagram under the conditions of 0.01–100 kPa and above 700 K.

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Phase equilibria in the system Ca4Al6O12SO4 – Ca2SiO4 – CaSO4 – H2O referring to the hydration of calcium sulfoaluminate cements

RILEM Technical Letters ◽

10.21809/rilemtechlett.2016.5 ◽

2016 ◽

Vol 1 ◽

pp. 10 ◽

Cited By ~ 39

Author(s):

Frank Winnefeld ◽

Barbara Lothenbach

Keyword(s):

Experimental Data ◽

Phase Diagram ◽

Phase Equilibria ◽

Calcium Sulfate ◽

Thermodynamic Calculations ◽

Initial Composition ◽

Calcium Sulfoaluminate ◽

Ternary Diagrams

This paper presents thermodynamic calculations of the stable hydrate assemblages in calcium sulfoaluminate cements containing different amounts of ye’elemite, calcium sulfate and belite. The ternary diagrams developed in this paper can be used directly to assess the long-term composition of such calcium sulfoaluminate cements containing belite. The phase diagram was validated using experimental data from literature. The ternary diagrams developed can be used to read out directly the stable hydrate assemblage of calcium sulfoaluminate cements containing belite based on their initial composition.

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Phase equilibria in the system Ca4Al6O12SO4 – Ca2SiO4 – CaSO4 – H2O referring to the hydration of calcium sulfoaluminate cements

RILEM Technical Letters ◽

10.21809/rilemtechlett.v1.5 ◽

2016 ◽

Vol 1 ◽

pp. 10 ◽

Cited By ~ 1

Author(s):

Frank Winnefeld ◽

Barbara Lothenbach

Keyword(s):

Experimental Data ◽

Phase Diagram ◽

Phase Equilibria ◽

Calcium Sulfate ◽

Thermodynamic Calculations ◽

Initial Composition ◽

Calcium Sulfoaluminate ◽

Ternary Diagrams

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Identifying Physico-Chemical Laws from the Robotically Collected Data

10.26434/chemrxiv.8490149 ◽

2019 ◽

Author(s):

Liwei Cao ◽

Danilo Russo ◽

Vassilios S. Vassiliadis ◽

Alexei Lapkin

Keyword(s):

Experimental Data ◽

Numerical Models ◽

Predictor Variable ◽

Physical Models ◽

Training Data ◽

Mixed Integer ◽

Physico Chemical ◽

Data Points ◽

Future Work ◽

The Relationship

A mixed-integer nonlinear programming (MINLP) formulation for symbolic regression was proposed to identify physical models from noisy experimental data. The formulation was tested using numerical models and was found to be more efficient than the previous literature example with respect to the number of predictor variables and training data points. The globally optimal search was extended to identify physical models and to cope with noise in the experimental data predictor variable. The methodology was coupled with the collection of experimental data in an automated fashion, and was proven to be successful in identifying the correct physical models describing the relationship between the shear stress and shear rate for both Newtonian and non-Newtonian fluids, and simple kinetic laws of reactions. Future work will focus on addressing the limitations of the formulation presented in this work, by extending it to be able to address larger complex physical models.

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The stability and electronic and photocatalytic properties of the ZnWO4 (010) surface determined from first-principles and thermodynamic calculations

RSC Advances ◽

10.1039/d1ra03218f ◽

2021 ◽

Vol 11 (38) ◽

pp. 23477-23490

Author(s):

Yonggang Wu ◽

Jihua Zhang ◽

Bingwei Long ◽

Hong Zhang

Keyword(s):

Phase Diagram ◽

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Thermodynamic Calculations ◽

Photocatalytic Properties ◽

Thermodynamic Approach ◽

Functional Theory ◽

Stability Phase Diagram ◽

The Stability

The ZnWO4 (010) surface termination stability is studied using a density functional theory-based thermodynamic approach. The stability phase diagram shows that O-Zn, DL-W, and DL-Zn terminations of ZnWO4 (010) can be stabilized.

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A Person-to-Person and Person-to-Place COVID-19 Contact Tracing System Based on OGC IndoorGML

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi10010002 ◽

2020 ◽

Vol 10 (1) ◽

pp. 2 ◽

Cited By ~ 1

Author(s):

Soroush Ojagh ◽

Sara Saeedi ◽

Steve H. L. Liang

Keyword(s):

Data Model ◽

Low Cost ◽

Large Body ◽

Contact Tracing ◽

Trajectory Data ◽

Sequential Order ◽

Human Contact ◽

Wide Availability ◽

Data Points ◽

The Impact

With the wide availability of low-cost proximity sensors, a large body of research focuses on digital person-to-person contact tracing applications that use proximity sensors. In most contact tracing applications, the impact of SARS-CoV-2 spread through touching contaminated surfaces in enclosed places is overlooked. This study is focused on tracing human contact within indoor places using the open OGC IndoorGML standard. This paper proposes a graph-based data model that considers the semantics of indoor locations, time, and users’ contexts in a hierarchical structure. The functionality of the proposed data model is evaluated for a COVID-19 contact tracing application with scalable system architecture. Indoor trajectory preprocessing is enabled by spatial topology to detect and remove semantically invalid real-world trajectory points. Results show that 91.18% percent of semantically invalid indoor trajectory data points are filtered out. Moreover, indoor trajectory data analysis is innovatively empowered by semantic user contexts (e.g., disinfecting activities) extracted from user profiles. In an enhanced contact tracing scenario, considering the disinfecting activities and sequential order of visiting common places outperformed contact tracing results by filtering out unnecessary potential contacts by 44.98 percent. However, the average execution time of person-to-place contact tracing is increased by 58.3%.

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Diffusion-induced in situ growth of covalent organic frameworks for composite membranes

Journal of Materials Chemistry A ◽

10.1039/c9ta11191c ◽

2019 ◽

Vol 7 (45) ◽

pp. 25802-25807 ◽

Cited By ~ 6

Author(s):

Priyanka Manchanda ◽

Stefan Chisca ◽

Lakshmeesha Upadhyaya ◽

Valentina-Elena Musteata ◽

Mark Carrington ◽

...

Keyword(s):

Reaction Times ◽

Composite Membranes ◽

Thin Layers ◽

In Situ Growth ◽

Covalent Organic Frameworks ◽

Polymeric Support ◽

Ambient Conditions ◽

Induction Method ◽

Covalent Organic Framework

Thin layers of a covalent organic framework (COF) have been synthesized on a flexible polymeric support using a new diffusion-induction method under ambient conditions in reaction times as short as 3 hours.

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Stoichiometry and disorder influence over electronic structure in nanostructured VOx films

Journal of Nanoparticle Research ◽

10.1007/s11051-020-05130-z ◽

2021 ◽

Vol 23 (1) ◽

Author(s):

A. D’Elia ◽

S. J. Rezvani ◽

N. Zema ◽

F. Zuccaro ◽

M. Fanetti ◽

...

Keyword(s):

Electronic Structure ◽

Distorted Octahedral Geometry ◽

Edge Structure ◽

Distorted Octahedral ◽

X Ray Absorption ◽

Complex Matter ◽

Nanometric Size

AbstractWe present and discuss the role of nanoparticles size and stoichiometry over the local atomic environment of nanostructured VOx films. The samples have been characterized in situ using X-ray absorption near-edge structure (XANES) spectroscopy identifying the stoichiometry-dependent fingerprints of disordered atomic arrangement. In vanadium oxides, the ligand atoms arrange according to a distorted octahedral geometry depending on the oxidation state, e.g. trigonal distortion in V2O3 and tetragonal distortion in bulk VO2. We demonstrate, taking VO2 as a case study, that as a consequence of the nanometric size of the nanoparticles, the original ligands symmetry of the bulk is broken resulting in the coexistence of a continuum of distorted atomic conformations. The resulting modulation of the electronic structure of the nanostructured VOx as a function of the oxygen content reveals a stoichiometry-dependent increase of disorder in the ligands matrix. This work shows the possibility to produce VOx nanostructured films accessing new disordered phases and provides a unique tool to investigate the complex matter.

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On the Fluctuation Induced Excess Conductivity in Stainless Steel Sheathed MgB2 Tapes

Journal of Materials ◽

10.1155/2013/898607 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 5

Author(s):

Suchitra Rajput ◽

Sujeet Chaudhary

Keyword(s):

Magnetic Field ◽

Experimental Data ◽

Stainless Steel ◽

Coherence Length ◽

Three Dimensional ◽

Excess Conductivity ◽

Scaling Functions ◽

Critical Fluctuations ◽

Scaling Models

We report on the analyses of fluctuation induced excess conductivity in the - behavior in the in situ prepared MgB2 tapes. The scaling functions for critical fluctuations are employed to investigate the excess conductivity of these tapes around transition. Two scaling models for excess conductivity in the absence of magnetic field, namely, first, Aslamazov and Larkin model, second, Lawrence and Doniach model, have been employed for the study. Fitting the experimental - data with these models indicates the three-dimensional nature of conduction of the carriers as opposed to the 2D character exhibited by the HTSCs. The estimated amplitude of coherence length from the fitted model is ~21 Å.

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Investigation of Emulsion Flow in Steam-Assisted Gravity Drainage

SPE Journal ◽

10.2118/157830-pa ◽

2013 ◽

Vol 18 (03) ◽

pp. 440-447 ◽

Cited By ~ 13

Author(s):

C.C.. C. Ezeuko ◽

J.. Wang ◽

I.D.. D. Gates

Keyword(s):

Experimental Data ◽

Numerical Simulation ◽

Oil Recovery ◽

Vital Role ◽

Gravity Drainage ◽

Steam Assisted Gravity Drainage ◽

Emulsion Flow ◽

Very High ◽

Effective Representation

Summary We present a numerical simulation approach that allows incorporation of emulsion modeling into steam-assisted gravity-drainage (SAGD) simulations with commercial reservoir simulators by means of a two-stage pseudochemical reaction. Numerical simulation results show excellent agreement with experimental data for low-pressure SAGD, accounting for approximately 24% deficiency in simulated oil recovery, compared with experimental data. Incorporating viscosity alteration, multiphase effect, and enthalpy of emulsification appears sufficient for effective representation of in-situ emulsion physics during SAGD in very-high-permeability systems. We observed that multiphase effects appear to dominate the viscosity effect of emulsion flow under SAGD conditions of heavy-oil (bitumen) recovery. Results also show that in-situ emulsification may play a vital role within the reservoir during SAGD, increasing bitumen mobility and thereby decreasing cumulative steam/oil ratio (cSOR). Results from this work extend understanding of SAGD by examining its performance in the presence of in-situ emulsification and associated flow of emulsion with bitumen in porous media.

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