Showing papers by "Istanbul Technical University published in 1988"
TL;DR: A detailed study of the Mesozoic palaeogeographic evolution of the Rhodope-Pontide fragment and the region surrounding the Black Sea as a whole was performed in this paper.
221 citations
TL;DR: A class of context-free languages is used to describe the fingerprint patterns and the recognition is accomplished using a sequential parsing technique to reduce the time requirement.
138 citations
62 citations
TL;DR: An exploratory study on the possible determinants of the extent of subcontracting by the construction firm is reported.
Abstract: A central concern in studying organization environment relationships has been the issue of how boundaries of organizational activity are defined and altered. A specific organizational response that pertains to the issue of boundaries is subcontracting. Construction is one industry where subcontracting is used extensively. Eccles' (1981a) study shows, however, that there is great variation in the subcontracting practices of contractors. This paper reports an exploratory study on the possible determinants of the extent of subcontracting by the construction firm.
41 citations
TL;DR: Aptian evaporites overlying oceanic crust on both sides of the South Atlantic between the Walvis Ridge and the Niger Delta were deposited in such a basin by repeated spilling of ocean water as discussed by the authors.
37 citations
TL;DR: In this paper, the authors examined the sulphur removal efficiency of pyrolysis from some Turkish lignites and found that the amount of sulphur removed increased up to 900 °C.
30 citations
13 citations
TL;DR: In this article, the topology of the flow field around a two-dimensional obstacle with different heights immersed in a turbulent boundary layer on a flat surface was investigated experimentally at a freestream velocity of 10 m s −1.
11 citations
TL;DR: Analyse des produits de la pyrolyse du lignite turc as discussed by the authors, separator de composes aliphatiques, aromatiques, and polaires de brais and analyse par plusieurs methodes chromatographiques.
Abstract: Analyse des produits de la pyrolyse du lignite turc. Separation de composes aliphatiques, aromatiques et polaires de brais et analyse par plusieurs methodes chromatographiques. Les echantillons sont analyses soit par injection directe d'un extrait du brais dans le dichloromethane, soit par extraction fluide supercritique, soit directement pendant la pyrolyse
10 citations
TL;DR: In this paper, the effect of air treatment on the desulfurization of seven Turkish lignites was investigated and the experimental results were presented Lignite samples were oxidized at 550 °C for 15 min using particles with diameters in the range 1-02 mm.
9 citations
TL;DR: A mixture of two incompressible Newtonian fluids is considered and the flow induced by steady vibrations of plates on poiseuille flow between two parallel plates, under a constant pressure gradient, is then investigated as mentioned in this paper.
TL;DR: In this article, the authors describe measurements in the turbulent shear flow behind a wing that is mounted on a flat plate at 30deg. of angle attack, including the skin-friction coefficient and pattern, the static pressure coefficient, and two mean velocity components.
Abstract: This paper describes measurements in the turbulent shear flow behind a wing that is mounted on a flat plate at 30Deg. of angle attack. Various physical aspects of the flow are illuminated by the experimental data that include the skin-friction coefficient and pattern, the static pressure coefficient, and two mean velocity components.
TL;DR: The reactions of cyclohexanone-formaldehyde-resin via its hydroxy and carbonyl functional groups with a number of different reagents such as acetic anhydride, benzoyl chloride, hydroxylamine, semicarbazide, and phenyl hydrazine were studied as mentioned in this paper.
Abstract: The reactions of cyclohexanone-formaldehyde-resin via its hydroxy and carbonyl functional groups with a number of different reagents such as acetic anhydride, benzoyl chloride, hydroxylamine, semicarbazide, and phenyl hydrazine were studied. Melting points, IR spectrums, and solubilities in various solvents of the products were determined.
Die Reaktionen eines Cyclohexanon-Formaldehyd-Harzes mit einer Anzahl verschiedener Reagentien, wie z. B. Essigsaureanhydrid, Benzoylchlorid, Hydroxylamin, Semicarbazid und Phenylhydrazin, wurden untersucht. Es wurden die Schmelzpunkte, IR-Spektren und Loslichkeiten der Produkte in verschiedenen Losungsmitteln bestimmt.
TL;DR: In this paper, the creep of lightweight aggregate concrete under constant stress is described by a logarithmic function of time, and the variations of the coefficients with age are experimentally determined.
Abstract: In this work, the creep of lightweight aggregate concrete under constant stress is described by a logarithmic function of time, and the variations of the coefficients with age are experimentally determined. Using the relation thus obtained, an attempt is made to predict the creep of lightweight concrete specimens with the same composition under stepwise varying stresses, assuming a linear viscoelastic behavior. It was established that there is good agreement between the predicted and experimental values.
TL;DR: In this paper, a priori atomic parameters (valence orbital nodal radii) were used to classify the stability of tetrahedral halocomplexes formed by polyvalent s-p metals in molten mixtures of their halides with alkali halides.
Abstract: We use a priori atomic parameters (valence orbital nodal radii) to classify the stability of tetrahedral halocomplexes formed by polyvalent s-p metals in molten mixtures of their halides with alkali halides. The present classification scheme for liquid mixtures parallels previous structural classifications for pure components in solid and molecular phases and is also essentially consistent with a stability criterion based on a Mott picture of a complex as a bound state in a conducting medium.
TL;DR: The influence of l'excentricite sur les variations de vitesse dans un mecanisme a came avec un poussoir anime d'un mouvement de translation as mentioned in this paper.
Abstract: Influence de l'excentricite sur les variations de vitesse dans un mecanisme a came avec un poussoir anime d'un mouvement de translation
TL;DR: In this paper, run-length characteristics and transition probabilities of such models are investigated by simulation for three different types of autocorrelation functions, and it is shown that these models can simulate persistent low flows as well as the phenomenon of differential persistence.
TL;DR: In this paper, a three-dimensional, pressured-riven, attached turbulent boundary-layer flow was made at Mach 0.4 and the mean velocities and the full Reynolds stress tensor were measured simultaneously by a three component LDA system.
Abstract: An experimental study of a three-dimensional, pressuredriven, attached turbulent boundary-layer flow was made at Mach 0.4. Both the mean velocities and the full Reynolds stress tensor were measured simultaneously by a three-component LDA system. Value of the resultant shear stress to turbulent kinetic energy ratio varied between 0.1 and 0.2 and did not remain constant across the boundary-layer. Slopes of the streamwise and azimuthal mixing length distributions in the wall region were around 0.4 and 1.2, respectively. Skew angle of the turbulent shear stress was larger than skew angle of the velocity gradient.
TL;DR: In this paper, the authors have shown how their approaches lead to assignments of the modes observed in the disordered β -phase, Raman spectrum at temperatures just below T c. The self-consistancy of various possible approaches to this problem is shown.
TL;DR: In this paper, the sulfur removal efficiency of carbonization by ammonia from seven Turkish lignites was examined at 700, 800 and 900 °C for time intervals of 5,15 and 30 min using one lignite.
TL;DR: In this paper, the optimal operation of reservoir systems of complex configuration is similar to that of simple reservoirs during dry periods, in order to optimize the firm water (energy) production, total release from the system should be kept constant.
Abstract: This study has shown that optimal operation of reservoir systems of complex configuration is similar to that of simple reservoirs during dry periods. In order to optimize the firm water (energy) production, total release from the system should be kept constant. To achieve this target individual reservoirs in the system will, in general, behave differently than they would if they were operated singly.
TL;DR: In this paper, a scheme for the quantization of scale-invariant gauge theories in higher dimensions is proposed, where the model is minimally coupled to a spinor field and regularization algorithms are proposed.
TL;DR: Etude de la repartition de la charge dans les differents cylindres d'un moteur a allumage par etincelle a six cylindre as mentioned in this paper.
Abstract: Etude de la repartition de la charge dans les differents cylindres d'un moteur a allumage par etincelle a six cylindres
TL;DR: In this article, a hybrid solution technique based on the concept of viscous-inviscid interaction was developed for studying external flow past three-dimensional bodies, where the 8-noded trilinear brick elements were used for the finite element formulation of the problem where the flow is considered potential.
Abstract: Based on the concept of viscous-inviscid interaction, a hybrid solution technique in studying external flow past three-dimensional bodies is developed. The finite element method is employed to solve the inviscid part of the flow and the finite difference technique is utilized in solving the viscous part of the flow. This hybrid technique is applied to study the flow past a swept bump on a circular cylinder. The 8-noded trilinear brick elements are used for the finite element formulation of the problem where the flow is considered potential. In the viscous part, however, three-dimensional boundary-layer equations simplified with small cross-flow assumption and expressed in the surface co-ordinates are solved utilizing the finite difference method. Numerical studies are made for both the laminar and the turbulent flow cases using the boundary-layer edge velocity distribution obtained through inviscid solution. The results are compared with the available experimental data. The boundary-layer edge velocity distribution is in good agreement with the experimental data; the prediction of the separation point for the laminar case is the same. For the turbulent flow case, the velocity profiles in the flow direction when compared to the measurements are overall in reasonably good agreement, and the discrepancies are due to small cross-flow assumption. However, the agreement concerning the wall shear stress component in the flow direction is more satisfactory.
TL;DR: In this paper, the first results of the analyses are presented, focusing on the variation characteristics of the precipitation type (thunderstorm and widespread) as well as to the variations of the distributions in short time intervals, that may be caused by different effects, for example the growth and decay of a precipitation cell or the movement of a cell combined with the different fall velocities of small and large drops.
Abstract: The knowledge of raindrop size distributions is of great interest to cloud physicists, radar meteorologists and communication engineers. Beginning from the Winter 1986–87, the Precipitation Group of the Atmospheric Physics Institute installed on the roof of the Institute building in Roma-Eur a disdrometer RD-69. The sensor is an electromechanical device with surface of 50 cm2 able to measure the raindrop diameter with a precision of 5% and a resolution (delay between two drops hitting the sensor) of one millisecond. After the calibration, significant precipitations were recorded continuously, with a sample period of 1 minute, during the whole life of the storms. It can be expected that a knowledge of the drop size distributions, and in particular of the differences between distrubitions, can be used to infer details of the storm and the environment. In this work the first results of the analyses are presented. Particular attention was conferred to the variation characteristics of the precipitation type (thunderstorm and widespread) as well as to the variations of the distributions in short time intervals, that may be caused by different effects, for example the growth and decay of a precipitation cell or the movement of a cell combined with the different fall velocities of small and large drops.
TL;DR: In this article, the authors constructed monopole solutions of the alternative scale invariant pure Yang-Mills models in six dimensions and Technological Research Council of Turkey (TRC-TEC).
TL;DR: The reaction of polymers containing carbonyl groups such as poly(methyl vinylketone), poly (methyl vinyl ketone-co-styrene) and polystyrene with phenol in the presence of HCI or H2SO4 has been studied in order to produce bisphenol A type structure on the polymer chain this paper.
Abstract: The reaction of polymers containing carbonyl groups such as poly(methyl vinylketone), poly(methyl vinyl ketone-co-styrene) and acetylated polystyrene with phenol in the presence of HCI or H2SO4 has been studied in order to produce bisphenol A type structure on the polymer chain. Poly(methyl vinyl ketone) shows intramolecular aldol condensation and acetylated polystyrene results in bisphenol A type structure.
Die Reaktion von Poly(methylvinylketon) und acetyliertem Polystyrol mit Phenol in Gegenwart von HCl oder H2SO4 wurde untersucht, um Polymere mit Strukturen ahnlich dem Bisphenol A zu erhalten. Die Reaktion an Poly(methylvinylketon) fuhrt zu intramolekularer Aldol-Kondensation, wahrend acetyliertes Polystyrol die gewunschte Bisphenol A-Struktur liefert.
TL;DR: In this paper, a non-linear least squares (NLLE) algorithm was used to analyze Raman data for ammonium halides close to phase transitions. But the analysis was performed in a more straight-forward way.
TL;DR: In this article, the infrared and Raman intensities can be related to the order parameter close to order-disorder phase transitions in crystal systems, and this relationship has been obtained and compared with our experimental results for ammonium halides.
Abstract: The infrared and Raman intensities can be related to the order parameter close to order-disorder phase transitions in crystal systems. In the present study this relationship has been obtained and compared with our experimental results for ammonium halides.