Showing papers by "Istanbul Technical University published in 1982"
TL;DR: In this article, the dislocation substructure developed on saturation was examined by transmission electron microscopy and an inverse relationship was found between the saturation stress and dislocation cell size, which appeared to be dependent upon the stacking fault energy of the particular material and independent of the type of deformation.
Abstract: Polycrystalline aluminum was cyclically deformed under strain control at room temperature in the as-extruded form and different annealed conditions after forging. The dislocation substructure developed on saturation was examined by transmission electron microscopy. An inverse relationship was found between the saturation stress and dislocation cell size. Comparison of these results with those for aluminum, copper, and iron obtained under both monotonie and cyclic conditions at various temperatures indicated that the same form of equation with a different constant was characteristic of each of the three wavy slip mode metals. The relationship appears to be dependent upon the stacking fault energy of the particular material and independent of the type of deformation(i.e., monotonie or cyclic).
40 citations
TL;DR: In this article, it has been shown that the standardized form of the deficit has a unique probability distribution for all values of level of regulation and autocorrelation coefficient of inflows.
16 citations
TL;DR: In this article, a constitutive theory for the generalized simple thermomechanical materials was developed by resorting to generalized thermodynamics in which the empirical temperature is replaced by the thermodynamic temperature which is itself constitutive function.
10 citations
TL;DR: In this article, the statical Reissner Sagoci problem for a transversely isotropic, nonhomogeneous elastic solid is investigated and the modulus of rigidity of the medium is assumed to be variable as a power of the radial coordinate in the form r β (β ⩾ 0).
10 citations
TL;DR: In this paper, the authors investigated the cuttability of evaporites and reported the results of a large-scale experimental work carried out in the Mining Engineering Department of the University of Newcastle upon Tyne.
Abstract: With ever-rising labour costs, the mining engineer and the underground civil engineer look to mechanical excavation systems to increase productivity. The research described in this paper was part of a major and long term programme of experimental work carried out in the Mining Engineering Department of the University of Newcastle upon Tyne. One of the objectives of this research was to investigate the cuttability of evaporites. To this end each rock which has been tested for its cutting properties has also been subjected to a wide range of physical and mechanical tests. All the results are discussed in this paper.
7 citations
TL;DR: In this paper, the geotechnical properties of the gypsum layer, encountered at the Sivas IVth Iron and Steel Complex Site, are investigated and an attempt is made to propose solutions to some of the problems anticipated at the site.
Abstract: In East and Middle Anatolia, where several heavy industrial plants are planned to be constructed, vast areas are covered by gypsiferous layers. In this investigation, geotechnical properties of the gypsum layer, encountered at the Sivas IVth Iron and Steel Complex Site, are investigated and an attempt is made to propose solutions to some of the geotechnical problems anticipated at the site. In the research several physical, chemical and engineering properties of gypsum, the changes caused by the environmental conditions on its mechanical behaviour and crystal structure, its stress-strain-time behaviour and effect on foundation concrete are investigated and recommendations on the precautions to be taken are presented.
6 citations
TL;DR: In this paper, a mathematical model for annual flows of some rivers exhibiting differential persistence is described, which is a three-state Markov model, where states of the Markov process are defined as low, normal and high flows with respect to a lower and an upper truncation level.
5 citations
TL;DR: The results of observations and investigations made after 1960, showed that besides anhydrite, clay minerals such as corrensite and montmorillonite have the property of swelling and that of stress releasing owing to gravitational and tectonic stresses and also preconsolidation properties which are responsible for deformation.
Abstract: Although the known evaporite minerals amount to more than 25, anhydrite and gypsum are the most conspicuous from the engineering geological point of view. They present considerable difficulties in the construction of tunnels, dams and other structures because of their solubility and swelling when treated with water. Swelling phenomena observed in anhydrites have been exaggerated before the 1960's. During those years anhydrite has been thought to be solely responsible for all kinds of harmful swelling effects. The results of observations and investigations made after 1960, showed that besides anhydrite, clay minerals such as corrensite and montmorillonite have the property of swelling and that of stress releasing owing to gravitational and tectonic stresses and also preconsolidation properties which are responsible for deformation.
4 citations
TL;DR: Synthetic and real data applications show that the present technique is superior to the optimum least-squares filters and straight stacking in recovering and enhancing the signal events with relatively high residual statics.
Abstract: Wavenumber aliasing is the main limitation of conventional optimum least-squares linear moveout filters: it prevents adequate reject domain weighting for efficient coherent noise rejection. A general frequency domain multichannel filter design technique based on a one-to-one mapping method between two-dimensional (2D) space and one-dimensional (1D) space is presented. The 2D desired response is mapped to the 1D frequency axis after a suitable sorting of the coefficients. A min-max or Tchebycheff approximation to the desired response is obtained in the 1D frequency domain and mapped back to the 2D frequency domain. The algorithm is suitable for multiband 2D filter design. No aliasing damage is inherent in the linear moveout filters designed using this technique because the approximation is done in the frequency-wavenumber (f, k)-domain.
Linear moveout filters designed by using the present coefficient mapping technique achieve better pass domain approximations than the corresponding conventional least-squares filters. Compatible reject domain approximations can be obtained from suitable mappings of the origin coefficient of the desired (f k)-response to the 1D frequency axis. The (fk)-responses of linear moveout filters designed by using the new technique show equi-ripple behavior. Synthetic and real data applications show that the present technique is superior to the optimum least-squares filters and straight stacking in recovering and enhancing the signal events with relatively high residual statics. Their outputs also show higher resolution than those of the optimum least-squares filters.
2 citations
01 Jan 1982
TL;DR: In this article, the unconstrained variational principles are formulated which yield, as the Euler equations, all the fundamental equations of a viscous incompressible fluid and an anisotropic elastic solid immersed within the fluid of finite extent, and their interface continuity conditions.
Abstract: The classical variational principles of fluid-solid interaction impose certain constraint as well as stringent interface conditions. The conditions which are often undesirable in obtaining approximate direct solutions are relaxed through Friedrichs’s transformation. Hence, the unconstrained variational principles are formulated which yield, as the Euler equations, all the fundamental equations of a viscous incompressible fluid and an anisotropic elastic solid immersed within the fluid of finite extent, and their interface continuity conditions.
1 citations
01 Jan 1982
TL;DR: In this paper, the same form of equation with a different constant was characteristic of each of the three wavy slip mode metals and the relationship appeared to be dependent upon the stacking fault energy of the particular material and independent of the type of deformation (ie. monotonic or cyclic).
Abstract: Polycrystalline aluminum and iron were cyclically deformed under strain control at room temperature. The corresponding dislocation substructures developed on saturation were examined by transmission electron microscopy. An inverse relationship was found between the saturation stress and dislocation cell size. Comparison of these results with those for aluminum, copper and iron obtained under both monotonic and cyclic conditions at various temperatures indicated that the same form of equation with a different constant was characteristic of each of the three wavy slip mode metals. The relationship appears to be dependent upon the stacking fault energy of the particular material and independent of the type of deformation (ie. monotonic or cyclic).