Browsing by Publisher "Assoc Sci Res"

Now showing 1 - 14 of 14
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    Analysis of unsteady flow in complex pipe system by the method of characteristics
    (Assoc Sci Res, 1998) Tezcan Tekin; Gokkus Umit; Sinir Gultekin
    This study aims at the unsteady flow analysis of complex pipe system by using the method of characteristics. Excess demand and sudden closure and opening of devices such as valves and pumps causes the occurrence of unsteady flow. Hydraulic analysis of pipe system is still performed only by steady-state flow. The unsteady flow analysis can be done by using the results of this analysis.
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    Approximate boundary layer solution of a moving beam problem
    (Assoc Sci Res, 1998) Pakdemirli M.; Ozkaya E.
    The transverse vibrations of a simply supported beam moving with constant velocity is considered. The case of transition from string to beam effects is treated. In this model, the fourth order spatial derivative multiplies a small parameter and hence leads to a boundary layer problem. The problem is solved approximately using the method of multiple scales.
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    Peiffer commutators by using GAP package
    (Assoc Sci Res, 1998) Mutlu Ali
    We describe Peiffer commutators within the Moore complex NG of a simplicial group G. The calculation of the Peiffer commutators is made by using GAP program.
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    Assessing environmental consequences of water projects based on a pseudo expert system approach
    (Assoc Sci Res, 1999) Yurdusev Mehmet Ali
    Environmental Impact Assessment (EIA) of any development project is now a part of the project analysis today. This is not only required by national and/or international legislation, but also the growing environmental awareness of societies has forced project implementers to consider any environmental consequences beforehand and take the necessary measures to mitigate adverse effects. As a project cycle may include several steps, the consideration of environmental impacts at each level is now something inevitable. Although large numbers of environmental impact assessment procedures are available, an appropriate EIA procedure that is compatible with the level must be adopted. To this end, a tailor-made procedure for water resources planning process is devised, which is a computer model for the environmental assessment of planning components such as reservoirs and abstraction schemes etc. The model provides all the necessary facilities and knowledge thereby assisting the user to evaluate a particular impact by means of generic knowledge in relation to the impact and the site characteristics. As such, the model takes a form of expert system without a proper shell being used. The intention is to use the outcomes of this model for including environmental impacts along with the economical considerations in large-scale water resources planning process.
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    Calculation of temperature distribution on a crown tooth by using three-dimensional finite element method
    (Assoc Sci Res, 1999) Aykul H.; Toparli M.; Koksal N.S.
    The finite element was used to temperature changes with time to Au-AgPd alloy and porcelain crowns in three dimensional models of average maxillary second premolar. Temperature changes some critical nodes were calculated as a result of hot/cold liquid. Calculation programs were prepared by authors using FORTRAN 77. The tooth was assumed isotropic, homogenous, elastic and unsymmetric.
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    Comparison of different versions of the method of multiple scales for an arbitrary model of odd nonlinearities
    (Assoc Sci Res, 1999) Pakdemirli Mehmet; Boyaci Hakan
    A general model of cubic and fifth order nonlinearities is considered. The linear part as well as the nonlinearities are expressed in terms of arbitrary operators. Two different versions of the method of multiple scales are used in constructing the general transient and steady-state solutions of the model: Modified Rahman-Burton method and the Reconstitution method. It is found that the usual ordering of reconstitution can be used, if at higher orders of approximation, the time scale corresponding to that order is considered and all other time derivatives are ignored. Results are applied to an example and steady-state solutions are compared numerically for both methods.
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    IBM-1 study for some Ce isotopes
    (Assoc Sci Res, 1999) Inan Sait; Yoruk Abdulkadir; Kucukbursa Atalay
    The structure of even-even Ce isotopes with neutron number 72≤N≤76 are studied within the framework of the Interacting Boson Model (IBM-1). The excitation energies and the B(E2) values of the above nuclei are calculated, it is found that the agreements between the calculated and observed data are much better in the model of the effective boson consideration.
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    On some extensions of Dynamical Homeomorphism and Dynamical Isomorphism in Dynamical System
    (Assoc Sci Res, 1999) Bildik Necdet; Inc Mustafa
    In this paper, the definitions and the theorems concerning with the invariant sets, w- and α-limit sets are given and proved in the new Dynamical Systems. By using of the definition of P+ and P- stability, some remarkable unknown results are obtained. Finally, the definition of Dynamical Isomorphism and Dynamical Homeomorphism are given and related original theorems are presented and proved.
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    Free 2-crossed complexes of simplicial algebras
    (Assoc Sci Res, 2000) Mutlu Ali
    Using free simplicial algebras, it is shown that a free or totally free 2-crossed module can be constructed on suitable construction data in [2]. In this paper 2-crossed complexes and freeness conditions for 2-crossed complexes are introduced and similar freeness results for these are discussed.
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    Join for (augmented) simplicial group
    (Assoc Sci Res, 2000) Mutlu Ali
    We introduced a notion of join for (augmented) simplicial groups generalising the classical join of geometric simplicial complexes. The definition comes naturally the ordinal sum on the base simplicial category Δ.
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    Uncertainty analysis of cryogenic turbine efficiency
    (Assoc Sci Res, 2000) Kanoglu Mehmet
    A procedure for estimating uncertainty in the hydraulic efficiency of cryogenic turbines is presented. A case study is performed based on the test data from a cryogenic turbine testing facility. The effects of uncertainties in the measurements of temperature, pressure, and generator power on the turbine hydraulic efficiency are studied and the uncertainty in turbine efficiency is estimated to be ±0.20%. About 79% of the uncertainty is determined to come from the uncertainty in generator power measurement. This uncertainty in turbine efficiency is believed to be reasonable and acceptable for the testing of cryogenic turbines.
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    On the nonlinear transverse vibrations and stability of an axially accelerating beam
    (Assoc Sci Res, 2000) Oz H.R.
    Nonlinear vibrations and stability analysis of an axially moving Euler-Bernoulli type beam are investigated. The beam is on fixed supports and moving with a harmonically varying velocity about a constant mean value. The method of multiple scales is used in the analysis. Nonlinear frequencies depending on vibration amplitudes are obtained. Stability and bifurcations of steady-state solutions are analyzed for frequencies close to two times any natural frequency. It is shown that the amplitudes are bounded in time for frequencies close to zero. The effect of fixed supports is discussed.
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    Calculation of the natural frequencies of a beam-mass system using finite element method
    (Assoc Sci Res, 2000) Oz H.R.
    In this study, the natural frequencies of an Euler-Bernoulli type beam with a mass are calculated. The beam is supported with different end conditions. The mass is located on different locations. The linear natural frequencies are calculated by using finite element method for the first five modes. Results are compared with those of exact and other approximate methods.
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    On approximate symmetries of a wave equation with quadratic non-linearity
    (Assoc Sci Res, 2000) Pakdemirli M.; Yurusoy M.
    Two different approximate symmetry methods and a proposed new one are contrasted using a wave equation with quadratic non-linearity. For each method, the approximate symmetries are calculated first. Then approximate solutions corresponding to some of the symmetries are calculated. It is found that a given specific approximate solution is attainable only by using the new proposed method.