Effects of B2O3 on Crystallization,Structure, and Heat Transfer of CaO-Al2O3-Based Mold Fluxes

Metallurgical and Materials Transactions B - The reaction between traditional CaO-SiO2-based mold fluxes and high-Al steel inevitably changes flux composition, and, consequently, flux properties....     

Transverse magnetoresistance peculiarities of thermoelectric Lu-doped Bi2Te3 compound due to strong electrical disorder

The n-type thermoelectric Bi_1.9Lu_0.1Te₃ was prepared by microwave-solvothermal method and spark plasma sintering. The magnetic field and temperature dependences of transverse magnetoresistance measured within temperature 2–200 K interval allow finding the peculiarities characteristic for strongly disordered and inhomogeneous semiconductors. The first peculiarity is due to appearance of linear-in-magnetic field contribution to the total magnetoresistance reflected in a crossover from quadratic magnetoresistance at low magnetic fields to linear magnetoresistance at high magnetic fields. The linear magnetoresistance can result from the Hall resistance picked up from macroscopically distorted current paths due to local variations in stoichiometry of the compound studied. The second peculiarity is that both linear magnetoresistance magnitude and crossover field are functions of carrier mobility which is in agreement with the Parish and Littlewood model developed for disordered and inhomogeneous semiconductors. An increase in the mobility due to a decrease in temperature is accompanied by an increase in the magnetoresistance magnitude and a decrease in the crossover field. Finally, the third peculiarity is related to the remarkable deviation of the total magnetoresistance measured at various temperatures from the Kohler's rule. Presence of strong inhomogeneity and disorder in the Bi_1.9Lu_0.1Te₃ structure concluded from the magnetoresistance peculiarities can be responsible for the remarkable reduction in the total thermal conductivity of this compound.     

The equilibrium partitioning of titanium between Ti3+ and Ti4+ valency states in CaO-SiO2-TiO x slags

The redox behavior of titanium in CaO-SiO₂-TiO _x melts was investigated using a slag-gas equilibrium technique. Titanium partitioning between Ti³⁺ and Ti⁴⁺ valency states and the ratio of activity coefficients of TiO_1.5 and TiO₂ were determined as functions of oxygen partial pressure, temperature, and slag composition. The equilibrium experiments were carried out at temperatures between 1783 and 1903 K under CO-CO₂-Ar gas atmosphere with oxygen partial pressure ranging from 10⁻¹² to 10⁻⁷ atm (1.01×10⁻¹⁰ kPa to 1.01×10⁻⁵ kPa). The slags had CaO/SiO₂ ratios between 0.55 and 1.35 and total titanium oxide concentrations from 7 to 50 mass pct. Experimental results showed that the Ti³⁺/Ti⁴⁺ ratio in CaO-SiO₂-TiO _x slags, containing up to 50 mass pct TiO _x , increased with decreasing oxygen partial pressure and decreased with increasing CaO/SiO₂ ratio and decreasing temperature. Measured variation of the redox ratio Ti³⁺/Ti⁴⁺ with oxygen partial pressure closely followed the ideal behavior. Increasing the CaO/SiO₂ ratio increased the ratio of activity coefficients of TiO_1.5 and TiO₂. The effect of total titania content on this ratio was more complex and in accord with Raman spectroscopy data.     

Synthesis of Sialon from Kaolin and Its Phase Formation

The main phase transformations during synthesis of β‐sialon from kaolin of the Prosyanovskii deposit (Ukraine) under test-industrial production conditions have been studied. Sialon was prepared by carbothermal reduction in graphite-tube furnaces in nitrogen. It is shown that the process is characterized by the simultaneous occurrence of several chemical reactions with formation of intermediate phases (Si₂ON₂, X₁‐phase), silicon carbide, and (apart from β‐sialon) sialons based on AlN polytypes. The phase composition of the final product is determined not only by the charge composition but also by the set of production parameters. Results of the work may provide a basis for commercial preparation of sialon powder.     

Effects of CaO/SiO2 Ratio and Na2O Content on Melting Properties and Viscosity of SiO2-CaO-Al2O3-B2O3-Na2O Mold Fluxes

Metallurgical and Materials Transactions B - This paper investigated the effects of CaO/SiO2 ratio (0.8 to 1.5) and Na2O concentration (6 to 9 wt pct) on melting properties and viscosity...     

Formation of a Network Structure in the Gaseous Reduction of Magnetite Doped with Alumina

Reduction of un-doped magnetite is developed topochemically with the formation of a dense iron shell. However, the reduction of alumina-doped magnetite to wüstite proceeds with the formation of a network-like structure which consists of criss-crossed horizontal and vertical plates of wüstite. Reduction of magnetite includes the conversion of Fe³⁺ to Fe²⁺ and the movement of iron cations from the tetrahedral sites on the {400} and {220} planes of magnetite to the octahedral sites on the {200} planes of wüstite. Alumina has a negligibly small solubility in wüstite. In the reduction of magnetite doped with Al₂O₃, rejected Al³⁺ cations from wüstite diffuse to the magnetite–hercynite solid solution. Enrichment of the Fe₃O₄–FeAl₂O₄ solution with alumina in the vicinity of the reduction interface restricts the growth of {220} planes of wüstite and nucleation of {220} planes adjusted to the existing planes, preventing the merging of wüstite plates during the reduction process. Reduction of magnetite from the magnetite–hercynite solid solution practically stops when the Al³⁺ content at the interface approaches the solubility limit. Wüstite in the separated plates is reduced further to iron.     

DVR3D: a program suite for the calculation of rotation-vibration spectra of triatomic molecules

The DVR3D program suite calculates energy levels, wavefunctions, and where appropriate dipole transition moments, for rotating and vibrating triatomic molecules. Potential energy and, where necessary, dipole surfaces must be provided. Expectation values of geometrically defined functions can be calculated, a feature which is particularly useful for fitting potential energy surfaces. The programs use an exact (within the Born-Oppenheimer approximation) Hamiltonian and offer a choice of Jacobi or Radau internal coordinates and several body-fixed axes. Rotationally excited states are treated using an efficient two-step algorithm. The programs uses a Discrete Variable Representation (DVR) based on Gauss-Jacobi and Gauss-Laguerre quadrature for all 3 internal coordinates and thus yields a fully point-wise representation of the wavefunctions. The vibrational step uses successive diagonalisation and truncation which is implemented for a number of possible coordinate orderings. The rotational, expectation value and transition dipole programs exploit the savings offered by performing integrals on a DVR grid. The new version has been rewritten in FORTRAN 90 to exploit the dynamic array allocations and the algorithm for dipole and spectra calculations have been substantially improved. New modules allow the z-axis to be embedded perpendicular to the plane of the molecule and for the calculation of expectation values.

Program summary

Title of the program: DVR3D suiteCatalogue number: ADTIProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTIProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandProgramming language: Fortran 90No. of lines in distributed program, including test data, etc.: 61 574No. of bytes in distributed program, including test data, etc.: 972 404Distribution format: tar.gz

New version summary

Title of program: DVR3DRJZCatalogue number: ADTBProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTBProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandReference in CPC to previous version: 86 (1995) 175Catalogue identifier of previous version: ADAKAuthors of previous version: J. Tennyson, J.R. Henderson and N.G. FultonDoes the new version supersede the original program?: DVR3DRJZ supersedes DVR3DRJComputer: PC running LinuxInstallation: desktopOther machines on which program tested: Compaq running True64 Unix; SGI Origin 2000, Sunfire V750 and V880 systems running SunOS, IBM p690 Regatta running AIXProgramming language used in the new version: Fortran 90Memory required to execute: case dependentNo. of lines in distributed program, including test data, etc.: 4203No. of bytes in distributed program, including test data, etc.: 30 087Has code been vectorised or parallelised?: The code has been extensively vectorised. A parallel version of the code, PDVR3D has been developed [1], contact the first author for detailsAdditional keywords: perpendicular embeddingDistribution format: gzNature of physical problem: DVR3DRJZ calculates the bound vibrational or Coriolis decoupled rotational-vibrational states of a triatomic system in body-fixed Jacobi (scattering) or Radau coordinates [2]Method of solution: All coordinates are treated in a discrete variable representation (DVR). The angular coordinate uses a DVR based on (associated) Legendre polynomials and the radial coordinates utilise a DVR based on either Morse oscillator-like or spherical oscillator functions. Intermediate diagonalisation and truncation is performed on the hierarchical expression of the Hamiltonian operator to yield the final secular problem. DVR3DRJ provides the vibrational wavefunctions necessary for ROTLEV3, ROLEV3B or ROTLEV3Z to calculate rotationally excited states, DIPOLE3 to calculate rotational-vibrational transition strengths and XPECT3 to compute expectation valuesRestrictions on the complexity of the problem: (1) The size of the final Hamiltonian matrix that can practically be diagonalised. (2) The order of integration in the radial coordinates that can be dealt with within the machine exponent range. Some adjustment in the code may be necessary when large order Gauss-Laguerre quadrature is usedTypical running time: Case dependent but usually dominated by the final (3D) matrix diagonalisation. The test runs take minutes on a fast PCUnusual features of the program: A user supplied subroutine containing the potential energy as an analytic function is a program requirementReferences:

[1]

H.Y. Mussa, J. Tennyson, Comput. Phys. Commun. 128 (2000) 434.

[2]

J. Tennyson, B.T. Sutcliffe, Internat. J. Quantum Chem. 42 (1992) 941.

New version summary

Title of program: ROTLEV3Catalogue number: ADTCProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTCProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandReference in CPC to previous version: 86 (1995) 175Catalogue identifier of previous version: ADALAuthors of previous version: J. Tennyson, J.R. Henderson and N.G. FultonDoes the new version supersede the original program?: YesComputer: PC running LinuxInstallation: desktopOther machines on which program tested: Compaq running True64 Unix; SGI Origin 2000, Sunfire V750 and V880 systems running SunOSProgramming language used: Fortran 90High speed storage required: case dependentNo. of lines in distributed program, including test data, etc.: 1514No. of bytes in distributed program, including test data, etc.: 12 652Has code been vectorised or parallelised?: The code has been extensively vectorised. A parallel version of the code, PROTLEV3 has been developed [1], contact the first author for detailsDistribution format: gzNature of physical problem: ROTLEV3 performs the second step in a two-step variational calculation for the bound rotational-vibrational levels of a triatomic system represented in either Jacobi or unsymmetrised Radau coordinatesMethod of solution: A basis is constructed from the solutions of the Coriolis decoupled problem provided by DVR3DRJZ. The angular coordinate is transformed back to a basis set representation. The sparse Hamiltonian matrix can be diagonalised iteratively or in coreRestrictions on the complexity of the problem: The size of matrix that can practically be diagonalisedTypical running time: Case dependent. The sample data takes less than a minute on a fast PCUnusual features of the program: Most data is read directly from DVR3DRJZ. ROTLEV3 can provide data to drive DIPOLE3 and/or XPECT3References: [1] H.Y. Mussa, J. Tennyson, Comput. Phys. Commun. 128 (2000) 434.

New version summary

Title of program: ROTLEV3BCatalogue number: ADTDProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTDProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandReference in CPC to previous version: 86 (1995) 175Catalogue identifier of previous version: ADAMAuthors of previous version: J. Tennyson, J.R. Henderson and N.G. FultonDoes the new version supersede the original program?: YesComputer: PC running LinuxInstallation: desktopOther machines on which program tested: Compaq running True64 Unix, Sunfire V750 and V880 systems running SunOSProgramming language used: Fortran 90High speed storage required: case dependentNo. of lines in distributed program, including test data, etc.: 2215No. of bytes in distributed program, including test data, etc.: 16 595Has code been vectorised or parallelised?: The code has been extensively vectorised. A parallel version of the code, PROTLEV3B has been developed [1], contact the first author for detailsDistribution format: gzNature of physical problem: ROTLEV3B performs the second step in a two-step variational calculation for the bound rotational-vibrational levels of a triatomic system represented by symmetrised Radau coordinates using a bisector embedding [2]Method of solution: A basis is constructed from the solutions of the Coriolis decoupled problem provided by DVR3DRJZ. The problem is constructed entirely within the DVR. The Hamiltonian matrix can be diagonalised iteratively or in coreRestrictions on the complexity of the problem: The size of matrix that can practically be diagonalisedTypical running time: Case dependent. The sample data takes a few minutes on a fast PCUnusual features of the program: Most data is read directly from DVR3DRJZ. ROTLEV3B can provide data to drive DIPOLE3 and/or XPECT3References:

[1]

H.Y. Mussa, J. Tennyson, Comput. Phys. Commun. 128 (2000) 434.

[2]

J. Tennyson, B.T. Sutcliffe, Internat. J. Quantum Chem. 42 (1992) 941.

Program summary

Title of program: ROTLEV3ZCatalogue number: ADTEProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTEProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandComputer: PC running LinuxInstallation: desktopOther machines on which program tested: Compaq running True64 Unix, Sunfire V750 and V880 systems running SunOSProgramming language used: Fortran 90High speed storage required: case dependentNo. of lines in distributed program, including test data, etc.: 2919No. of bytes in distributed program, including test data, etc.: 17 241Keywords: rotationally excited state, Coriolis coupling, secondary variational method, sparse matrix, vectorised, perpendicular embedding, Radau coordinatesHas code been vectorised or parallelised?: The code has been extensively vectorisedDistribution format: gzNature of physical problem: ROTLEV3Z performs the second step in a two-step variational calculation for the bound rotational-vibrational levels of a triatomic system represented by symmetrised Radau coordinates using a perpendicular embedding [1]Method of solution: A basis is constructed from the solutions of the Coriolis decoupled problem provided by DVR3DRJZ. The problem is constructed entirely within the DVR. The Hamiltonian matrix is diagonalised in coreRestrictions on the complexity of the problem: The size of matrix that can practically be diagonalisedTypical running time: Case dependent. The sample data takes a few minutes on a fast PCUnusual features of the program: Most data is read directly from DVR3DRJZReferences: [1] M.A. Kostin, O.L. Polyansky, J.Tennyson, J. Chem. Phys. 116 (2002) 7564.

New version summary

Title of program: DIPOLE3Catalogue number: ADTFProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTFProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandReference in CPC to previous version: 86 (1995) 175Catalogue identifier of previous version: ADANAuthors of previous version: J. Tennyson, J.R. Henderson and N.G. FultonDoes the new version supersede the original program?: YesComputer: PC running LinuxInstallation: desktopOther machines on which program tested: Compaq running True64 Unix; SGI Origin 2000; sunfire V750 and V880 systemsProgramming language used: Fortran 90High speed storage required: case dependentNo. of lines in distributed program, including test data, etc.: 1921No. of bytes in distributed program, including test data, etc.: 15 685Has code been vectorised or parallelised?: The code has been extensively vectorised. Commands to parallelise the code using OpenMP are included in the sourceDistribution format: gzNature of physical problem: DIPOLE3 calculates dipole transition intensities between previously calculated wavefunction for both rotational and rotational-vibrational transitionsMethod of solution: Integrals over dipole surfaces are constructed using a DVR in all three coordinates, this requires a transformation of the angular wavefunctions. Wavefunctions generated by DVR3DRJZ and ROTLEV3 or ROTLEV3B are then used to give transition intensities for individual pairs of statesRestrictions on the complexity of the problem: The complexity of the problem that can be solved by DVR3DRJZ, ROTLEV3 or ROTLEV3BTypical running time: Case dependent. The test data takes a few seconds on a fast PCUnusual features of the program: Most data is read directly from DVR3DRJZ and ROTLEV3 or ROTLEV3B. DIPOLE provides data to drive SPECTRA

New version summary

Title of program: SPECTRACatalogue number: ADTGProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTGProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandComputer: PC running LinuxInstallation: desktopOther machines on which program tested: Compaq running True64 UnixReference in CPC to previous version: 75 (1993) 339Catalogue identifier of previous version: ACNBAuthors of previous version: J. Tennyson, S. Miller and C.R. Le SueurDoes the new version supersede the original program?: YesProgramming language used: Fortran 90High speed storage required: case dependentNo. of lines in distributed program, including test data, etc.: 1037No. of bytes in distributed program, including test data, etc.: 9159Has code been vectorised or parallelised?: As execution times are very short this is usually not importantDistribution format: gzNature of physical problem: SPECTRA generates synthetic, frequency ordered spectra as a function of temperature. Absolute intensities can be calculated if the necessary data to calculate the partition function is suppliedMethod of solution: Transitions are sorted by frequency and weighted using Boltzmann statisticsRestrictions on the complexity of the problem: The complexity of problem that can be solved by other programs in the suiteTypical running time: Case dependent, but very small for sample dataUnusual features of the program: Most data is read directly from DIPOLE3. Some data from DVR3DRJZ and ROTLEV3 or ROTLEV3B may also be required

Program summary

Title of program: XPECT3Catalogue number: ADTHProgram summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTHProgram obtainable from: CPC Program Library, Queen's University of Belfast, N. IrelandComputer: PC running LinuxInstallation: desktopOther machines on which program tested: Compaq running True64 UnixProgramming language used: Fortran 90High speed storage required: case dependentNo. of lines in distributed program, including test data, etc.: 1214No. of bytes in distributed program, including test data, etc.: 9361Distribution format: gzKeywords: Expectation values, Hellmann-Feynman theorem, potential fittingHas code been vectorised or parallelised?: The code has been extensively vectorisedNature of physical problem: XPECT3 calculates expectation of geometrically defined operators using previously calculated wavefunctionsMethod of solution: Integrals over the user defined surfaces are constructed using a DVR in all three coordinates. Wavefunctions generated by DVR3DRJZ and ROTLEV3 or ROTLEV3B are then used to give expectation values for each stateRestrictions on the complexity of the problem: The complexity of problem that can be solved by DVR3DRJZ, ROTLEV3 or ROTLEV3BTypical running time: Case dependent. The test data takes a few seconds on a fast PCUnusual features of the program: Most data is read directly from DVR3DRJZ and ROTLEV3 or ROTLEV3B.     

Multi-stage programming with functors and monads: Eliminating abstraction overhead from generic code

We use multi-stage programming, monads and Ocaml’s advanced module system to demonstrate how to eliminate all abstraction overhead from generic programs, while avoiding any inspection of the resulting code. We demonstrate this clearly with Gaussian Elimination as a representative family of symbolic and numeric algorithms. We parameterize our code to a great extent-over domain, input and permutation matrix representations, determinant and rank tracking, pivoting policies, result types, etc.-at no run-time cost. Because the resulting code is generated just right and not changed afterward, MetaOCaml guarantees that the generated code is well-typed. We further demonstrate that various abstraction parameters (aspects) can be made orthogonal and compositional, even in the presence of name-generation for temporaries, and “interleaving” of aspects. We also show how to encode some domain-specific knowledge so that “clearly wrong” compositions can be rejected at or before generation time, rather than during the compilation or running of the generated code.     

Optimization of workcell layouts in a mixed-model assembly line environment

Mixed-model assembly lines enable automotive manufacturers to build different vehicles using the same equipment and facility. They allow a more rapid response to changes in customer demand. However, the increased production flexibility creates new challenges regarding assembly line planning and balancing. Part of this problem is how to allocate stock within the workcells so that non-value added operations, such as walking and waiting, are minimized. This paper addresses the issue of workstation layout optimization. Different formulations can be used to minimize non-value added time depending on the level of sophistication desired. We present three different optimization formulations and give an example of an optimized workstation layout.