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ABSTRACT This study presents the determination of modal properties of a historical masonry palace built between 1861 and 1865 in lstanbul. Both an experimental and a numerical study have been [...]

We describe rabacus, a Python package for calculating the transfer of hydrogen ionizing radiation in simplified geometries relevant to astronomy and cosmology. We present example solutions for three specific cases: (1) a semi-infinite slab gas distribution in a homogeneous isotropic background, (2) a spherically symmetric gas distribution with a point source at the center, and (3) a spherically symmetric gas distribution in a homogeneous isotropic background. All problems can accommodate arbitrary spectra and density profiles as input. The solutions include a treatment of both hydrogen and helium, a self-consistent calculation of equilibrium temperatures, and the transfer of recombination radiation. The core routines are written in Fortran 90 and then wrapped in Python leading to execution speeds thousands of times faster than equivalent routines written in pure Python. In addition, all variables have associated units for ease of analysis. The software is part of the Python Package Index and the source code is available on Bitbucket at https://bitbucket.org/galtay/rabacus. In addition, installation instructions and a detailed users guide are available at http://pythonhosted.org//rabacus.

In relation to temperature-dependent anisotropic materials, this paper develops the two-dimensional dynamic equations of an elastic plate with large deflections under the thermomechanical loading. The nonisothermal plate equations, formulated in invariant differential and invariant variational forms, are deduced from the three-dimensional equations of coupled thermoelasticity with second sound by means of a recent variational principle together with Mindlin’s kinematic hypothesis of elastic plates. Some cases involving special material, motion, and geometry are indicated, and a theorem of uniqueness is derived so as to ensure unique solutions of the fully linearized thermoelastic plate equations.

A variant of fetal hemoglobin (Hb F-Malta-I) has been detected and quantitated in adult blood with a sensitive radioimmunoassay employing monospecific anti-sera. The concentration of Hb F-Malta-I was 0.002–0.05%, with an average value of 0.011%. The ratio of Hb F-Malta-I/Hb F in adults was about 4.8%, compared to a ratio of about 27% in the newborn. Since the F-Malta-I variant is a product of a mutated G? locus, which is one of the nonallelic structural genes directing the ? chain synthesis, its presence in blood of adults shows that the synthesis of this gene is not completely suppressed after birth, as was previously suggested.

Guided by the principle of virtual work, the governing equations describing the physical behavior of a thermoelastic continuum were expressed as the Euler-Lagrange equations of certain variational principles. The differential variational principles were formulated for the thermoelastic continuum with or without an internal surface of discontinuity by introducing the dislocation potentials and Lagrange undetermined multipliers. These principles were shown to recover some of the earlier variational principles as special cases, and their reciprocals were also recorded.

In view of a recent extensive review concerning wave propagation in porous media [M. Y. Corapciog˘lu, in TransportProcessesinPorousMedia (Kluwer, Dordrecht, 1991), pp. 373–469], this paper presents a theory for the dynamic response of a multilayer plate within the frame of Biot′s theory of elasticity and consolidation for a porous anisotropic solid [M. A. Biot, J. Appl. Phys. 26, 182–185 (1955)]. The multilayer plate may comprise any number of bonded layers, each with a distinct but uniform thickness and anisotropic elastic properties. A differential variational principle [G. A. Altay and M. C. Do¨kmeci, J. Acoust. Soc. Am. 95, 3007 (A) (1994)] for Biot’s theory together with Mindlin’s plate kinematics for each layer is used to derive the two‐dimensional approximate equations of multilayer plate in invariant differential and variational forms. All the continuity conditions between the interfaces of layers are taken into account. The governing equations are capable of predicting the extensional, flexural, torsional, and coupled vibrations of multilayer poroelastic plates. Special cases involving the geometry, material, and motions of multilayer plates are studied. The results contain some of earlier ones as special cases. [Work supported in part by TU¨BA‐TU¨BI˙TAK.]

A unified procedure based on a general principle of physics (e.g., Hamilton’s principle) together with Legendre’s (or Friedrichs’s) transformation is proposed to systematically derive certain variational principles for discontinuous electromagnetic fields which are useful to treat electromagnetic waves and vibrations in dielectrics. The integral and differential types of variational principles generate Maxwell’s equations and the associated natural boundary and jump conditions as well as the initial conditions, as their Euler–Lagrange equations, for a regular finite and bounded dielectric region with or without a fixed, internal surface of discontinuity. Special cases of the variational principles, including a reciprocal one, are recorded which have those for time‐harmonic motions and a dielectric region within a vacuum or a perfect conductor, and they are shown to agree with and to recover some of earlier variational principles [e.g., M. C. Do¨kmeci, IEEE Trans. UFFC UFFC‐35, 775–787 (1988); UFFC‐37, 369–385 (1990) and G. A. As¸kar, 3007 (1994) and references therein]. [Work supported in part by The Scientific and Technical Research Council of Turkey.]

Context.The UV escape fraction from high-redshift galaxies plays a key role in models of cosmic reionisation. Because it is currently not possible to deduce the escape fractions during the epoch of reionisation from observations, we have to rely on numerical simulations.Aims.We aim to better constrain the escape fraction from high-redshift dwarf galaxies, as these are the most likely sources responsible for reionising the Universe.Methods.We employ a N-body/SPH method that includes realistic prescriptions for the physical processes that are important for the evolution of dwarf galaxies. These models are post-processed with radiative transfer to determine the escape fraction of ionising radiation. We perform a parameter study to assess the influence of the spin parameter, gas fraction and formation redshift of the galaxy and study the importance of numerical parameters as resolution, source distribution and local gas clearing.Results.We find that the UV escape fraction from high-redshift dwarf galaxies that have formed a rotationally supported disc lie between 10-5and 0.1. The mass and angular momentum of the galaxy are the most important parameters that determine the escape fraction. We compare our results to previous work and discuss the uncertainties of our models. Conclusions.The low escape fraction we find for high-redshift dwarf galaxies is balanced by their high stellar content, resulting in an efficiency parameter for stars that is only marginally lower than the values found by semi-analytic models of reionisation. We therefore conclude that dwarf galaxies play an important role in cosmic reionisation also after the initial starburst phase, when the gas has settled into a disc.

In relation to electroceramic media subject to large driving voltages, this paper presents the one‐dimensional nonlinear equations of a cylindrical ceramic bar. The field variables of the ceramic bar are all expanded in the power series expansions of its cross‐sectional coordinates. By means of a unified variational principle, which is formulated through Hamilton’s principle and Legendre’s transformation [e.g., M. C. Do¨kmeci, IEEE Trans. UFFC 35, 775–787 (1988)] together with the series expansions of field variables, the one‐dimensional electroelastic equations are systematically derived in both differential and variational forms. They are capable of predicting the extensional, flexural, and torsional as well as coupled motions of a ceramic bar at low and high frequencies. By a proper truncation of the series expansions, the electroelastic equations incorporate as many higher‐order effects as deemed desirable in any case. Special cases are investigated [cf. M. C. Do¨kmeci, Int. J. Solids Struct. 10, 401–409 (1974) and Proceedingsofthe 40thAnnualSymposiumonFrequencyControl (IEEE, New York, 1986), pp. 168–178]. The uniqueness is examined in solutions of the linearized electroelastic equations. [Work supported in part by The Scientific and Technical Research Council of Turkey.]

This study presents a general theory for the motions of a ceramic shell in which there is coupling among mechanical, electrical, and thermal fields. The coated ceramic shell is treated as a two‐dimensional thermopiezoelectric medium and a separation of variables solution in terms of the thickness coordinates, the midsurface coordinates, and time is sought for its field variables. Then, a variational averaging procedure [M. C. Do¨kmeci, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 35, 775–787 (1988)] together with the solution is used so as to derive the system of approximate equations of ceramic shell. The invariant system of governing equations which are expressed in both differential and variational forms accounts for all the types of motions of ceramic shells. Certain cases involving special geometry, material properties, and motions are considered [e.g., M. C. Do¨kmeci, J. Math. Phys. 19, 109–126 (1978)]. Also, the sufficient boundary and initial conditions are given for the uniqueness in solutions of the fully linearized system of shell equations. The results are shown to generate a series of known shell theories [e.g., M. C. Do¨kmeci, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 37, 369–385 (1990) and references therein]. [Work supported by TU¨BA‐TU¨BI˙TAK.]