Showing papers by "Istanbul University published in 1978"
TL;DR: In this article, the authors used a stereo-photogrammetric system coupled with a stroboscope to study the particle motion near the bottom of a turbulent open channel flow.
Abstract: This study continues the investigation of particle motions near the bottom in a turbulent open channel flow, reported by Sumer & Oguz (1978; hereafter referred to as part 1). Paths of suspended heavy particles were recorded in three dimensions and in time, employing a stereo-photogrammetric system coupled with a stroboscope. In the case of smooth bottom, the measured kinematical quantities concerning the particle motions were found to be in accord with the available information on the ‘bursting process’. Agreement between the particle motion and the bursting process provided further support for the mechanism of particle suspension near the bottom proposed in part 1. Similar experiments were carried out when the bottom was rough. Comparison between the smooth- and rough-bottom cases could be made on the same basis as the flow Reynolds number as well as the particle properties were kept almost unchanged in both the smooth and rough boundary experiments. The observations showed that particle motions close to the rough bottom are very similar in character to those in the smooth-bottom case. The findings of the present paper suggested that the suspension mechanism given for the smooth-boundary flow could be extended to the rough-boundary case.
211 citations
TL;DR: The structure of the E. coli ribosome is discussed that provides insight into the ribosomal mechanisms at the molecular level, and nonenzymic polypeptide synthesis may yield a suitable and simple assay system for investigating the interactions among tRNA, mRNA, and ribsomal components during translocation.
Abstract: Publisher Summary This chapter discusses that protein synthesis is a complex process involving multiple steps and requiring numerous cellular components. It reviews that the role of GTP in protein synthesis is the subject of numerous studies and speculations. It discusses the structure of the E. coli ribosome that provides insight into the ribosomal mechanisms at the molecular level. The translocation step as a central event of the ribosomal elongation process still remains as obscure as ever. Nonenzymic polypeptide synthesis may yield a suitable and simple assay system for investigating the interactions among tRNA, mRNA, and ribosomal components during translocation. The mechanism of elongation in eukaryotes is, in many ways, similar to the one in prokaryotes. Thus far, only EF-1 has proved to differ from the corresponding factor EF-T. The chapter also provides an overview on the eukaryotic elongation mechanism, its structure and mechanism of action of EF-1.
50 citations
TL;DR: The data indicate that the development (accumulation of dry matter) of the seeds is separable from the senescence response in soybeans, and therefore the seeds may function as more than sinks.
Abstract: MONOCARPY, a single flowering phase followed by senescence and death, is a widespread phenomenon in seed plants, particularly field crops, whose large monocultures put on a dramatic display during their senescence phase1–4. In many, but apparently not all monocarpic species, defruiting or deflowering ,can prevent or at least delay monocarpic senescence and death1–4. For some species such as soybeans, the killing influence has been traced to the developing seeds5. The conspicuous correlation between the accumulation of nutrients in the developing fruit and the senescence (or apparent ‘exhaustion’) of the leaves (Fig. 1) has led to the sugegstion that developing fruits cause senescence by diverting or withdrawing needed nutrients or hormones from the leaves and other vegetative parts1–4. Here we explore the relationship between nutrient (or hormone) withdrawal or diversion and foliar senescence. Our data indicate that the development (accumulation of dry matter) of the seeds is separable from the senescence response in soybeans, and therefore the seeds may function as more than sinks.
44 citations
TL;DR: Over a period of several years, drug studies conducted at the Missouri Institute of Psychiatry and replicated in Turkey suggested that discharge problems of schizophrenia patients in both countries were severe, but diametrically opposed in nature.
18 citations
18 citations
TL;DR: Two new cobalt diaminoglyoxime complexes have been prepared under SO 2 and NO atmospheres and their thermal decomposition investigated using TG-DTG-DTA techniques simultaneously as mentioned in this paper.
16 citations
TL;DR: In this paper, a general mathematical model for the generation of synthetic monthly flows is developed and the relevance of the model is its simultaneous preservation of lag zero cross-correlations between successive months together with the first-order serial correlation of each month.
Abstract: A general mathematical model for the generation of synthetic monthly flows is developed. The relevance of the model is its simultaneous preservation of lag-zero cross-correlations between successive months together with the first-order serial correlation of each month. It is shown that the conventional lag-one Markov model and the Thomas-Fiering model are special cases of the model presented. All of the necessary analytical expressions of the correlation structure of the model are derived. Finally, the fitting of the model to monthly flow data and the generation of synthetic sequences are discussed.
10 citations
9 citations
01 Aug 1978
TL;DR: In this paper, Bimolecular films between the sheets of inorganic layer crystals prepared by cation exchange and intercalation are compared with surface films in condensed and expanded states.
Abstract: Bimolecular films between the sheets of inorganic layer crystals prepared by cation exchange and intercalation are compared with surface films in condensed and expanded states. Thermal phase transitions of the films are followed by X-ray measurements. Typical phase transitions are the formation of different types of kink-blocks and at higher temperatures gauche-blocks. The rearrangement of kink-blocks into gauche-blocks corresponds to the transition of monomolecular films from condensed into expanded states.
6 citations
TL;DR: In this article, the small amplitude torsional oscillations of a hyperelastic infinite circular cylindrical thick tube made of a rubber-like material subjected to a large static internal and external pressure were investigated.
6 citations
TL;DR: In this article, a general synthesis method for the realisation of the nth-order lowpass voltage transfer function by the active R circuit containing n operational amplifiers and 4n resistors is given.
Abstract: A general synthesis method is given for the realisation of the nth-order lowpass voltage transfer function by the active R circuit containing n operational amplifiers and 4n resistors.
TL;DR: In this paper, a two-dimensional temperature and stress distribution for an orthotropic elastic body having a rectangular boundary is examined for situations in which one edge of the rectangle experiences an arbitrary variation of temperature, heat flow or convection, while each of the remaining edges is either insulated or maintained at the initial temperature.
Abstract: Stationary two-dimensional temperature and stress distributions are examined for an orthotropic elastic body having a rectangular boundary. Temperature fields are determined for situations in which one edge of the rectangle experiences an arbitrary variation of temperature, heat flow or convection, while each of the remaining edges is either insulated or maintained at the initial temperature. Displacement potentials are then used to find the thermal stresses for those cases in which the temperature remains constant over two opposite ends of the rectangle. As an illustrative example, the temperature and stresses resulting from a uniform temperature rise over a portion of one edge of the rectangle are computed; numerical results are given for a fibre-reinforced composite material.
TL;DR: The new hydroxymethyl compounds 1c and 2c, and the hydroxyethyl-9,10-anthraquinones 1d-f and 2d, respectively, have been obtained by alkylation of quinizarin (1a) and its monomethyl ether 2a with formaldehyde according to the method by Marschalk as discussed by the authors.
TL;DR: In this article, a new method for determining the initial values of state variables in active RLC networks is described, based on the consideration of switches as independent sources, and the state equations are extended to cover this situation, and their solution at t = 0+ gives the initial conditions that have been sought.
Abstract: A new method is described of determining the initial values of state variables in active RLC networks. This method utilizes neither the conservation principle of charges and fluxes nor the theory of distributions. An RLC active network is assumed to be formed at t = 0 by joining or disconnecting the elements that are contained in it, this operation being performed by the use of a set of switches. The new method is based on the consideration of switches as independent sources, and the state equations are extended to cover this situation, and their solution at t = 0+ gives the initial conditions that have been sought. Further, the new method is applicable to any state-space formulation techniques used.
TL;DR: In this article, two-dimensional spline functions were utilized in the solution of linear parabolic partial differential equations which describe the transient flow of water in porous aquifers with and without a sink within the domain.
TL;DR: In this paper, the authors present a method for finding all the a priori possible mechanisms of a certain number of steps for a given type of overall reaction, applied to finding the possible two-step mechanisms for: overall reactions of the type of molecular rearrangements, and of the kind of molecular associations.
Abstract: The method, presented for finding all thea priori possible mechanisms of a certain number of steps for a given type of overall reaction, is applied to finding the possible two-step mechanisms for: overall reactions of the type of molecular rearrangements, and of the type of molecular associations. Many examples from organic, physical or biochemistry are given such as mutarotation of glucose, Henry-Michaelis-Menten enzyme mechanism, rearrangements of halogenoamines, hydration of epoxides, etc. The approach provides a systematics for otherwise diverse mechanisms.
TL;DR: Kayinda ardaklanma, mesede kahverengi seritlilik ile her iki agac cinsinde catlamanin onlenmesi uzerine bir deneme
Abstract: Kayinda ardaklanma, mesede kahverengi seritlilik ile her iki agac cinsinde catlamanin onlenmesi uzerine bir deneme
TL;DR: Turkiye’nin onemli bazi orman agac turleri kerestelerininin teknik kurutma ozellikleri uzerine arastirmalar.
Abstract: Turkiye’nin onemli bazi orman agac turleri kerestelerinin teknik kurutma ozellikleri uzerine arastirmalar
01 Jan 1978
TL;DR: The herbage of Euphorbia lanata contained octaeosanol, octacosyl behenate, sitosteryl 3-s-D-glucoside, kaempferol 7-0-rhamnoside, quercetin 7 -0-digalactoside and aesculetin this paper.
Abstract: The herbage of Euphorbia lanata contained octaeosanol, octacosyl behenate, sitosteryl 3-s-D-glucoside, kaempferol 7-0-rhamnoside, kaempferol 3-0-ga-lactoside, quercetin 7-0-digalactoside, and aesculetin.
TL;DR: In this article, it has been shown that for a polarizable layer as a transmission medium, there is an indirect proportionality between the frequency effect (fe) in induced polarization and the wave number of the electrical induced field making use of this relationship for a two layered earth a polarization transform function has been obtained.
Abstract: It has been shown that for a polarizable layer as a transmission medium there is an indirect proportionality between the frequency effect (fe) in induced polarization (IP) and the wave number of the electrical induced field Making use of this relationship for a two layered earth a polarization transform function has been obtained Since the mathematical expression for the polarization transform function is the same as that of the resistivity transform function, it is possible to make direct interpretation for IP frequency effect field curves Thus, AA or QQ type resistivity sequences can be interpreted from induced polarization response of a horizontally stratified earth without resistivity extrema
A depth factor has been defined in order to obtain the true depth using the apparent depth In this way, some electromagnetic effects between horizontal layers with different polarizabilities can partly be eliminated
TL;DR: After repeated use for several times the immobilized toxin retains 75% of its activity as evidenced by ADP-ribosylation of elongation factor II and Kinetics of this reaction are reported.
Abstract: Commercially available diphtheria toxin was immobilized on nylon stocking material by a covalent activation of the polymeric material. Toxin was bound both directly to nylon as well as to nylon-polyethyleneimine copolymer. The immobilized toxin retained some of its catalytic activity as evidenced by ADP-ribosylation of elongation factor II. Kinetics of this reaction are reported. After repeated use for several times the immobilized toxin retains 75% of its activity.
TL;DR: In this paper, a system of p-tuple series equations, involving associate Legendre functions, related to the scattering of electromagnetic waves by a spherical surface divided into p parallel strips with different impedances is studied.
Abstract: A system of p-tuple series equations, involving associate Legendre functions, related to the scattering of electromagnetic waves by a spherical surface divided into p parallel strips with different impedances is studied. The original problem of solving a system composed of two p-tuple series equations is reduced to a problem of solving 2(2p—1) (or two) completely independent p-tuple series equations with the same kernel as well as a system of linear algebraic equations. The solutions to the independent series equations can be found by successive iterations. The conditions wich guarantee the convergence of the iterations and the uniqueness of the solution are given in two theorems. The results are applied to a simple illustrative example.
Es wird ein System von p-Tupel Reihengleichungen untersucht, das die Dispersion elektromagnetischer Wellen an einer spharischen Flache beschreibt, die aus p parallelen Streifen mit verschiedenen Impedanzen besteht. Das ursprungliche Problem, ein System von zwei p-Tupel Reihengleichungen zu losen, wird auf das Problem reduziert, die Losung von 2(2p—1) (oder zwei) unabhangigen p-Tupel Reihengleichungen mit demselben Kern und eines Systems linearer algebraischer Gleichungen zu bestimmen. Die Losungen der unabhangigen Reihengleichungen werden mittels sukzessiver Iterationen ermittelt. Die Bedingungen, die die Konvergenz der Iterationen und die Eindeutigkeit der Losung gewahrleisten, werden in zwei Satzen formuliert. Die Resultate werden an einem einfachen Beispiel illustriert.
01 Jan 1978
TL;DR: This paper represents the research conducted to review the state-of-the-art of control theories for the organizations from the systems viewpoint and its implementation in Turkey.
Abstract: This paper represents the research conducted to review the state-of-the-art of control theories for the organizations from the systems viewpoint and its implementation in Turkey.
TL;DR: A new cardiotonic pentaglycoside with the structure glucoacetyldigoxoside (digoxigenin-β-D-glucosido-acetyltetradigitoxosides) was isolated from the leaves ofDigitalis schischkinii (Ivan.) Werner as mentioned in this paper.
Abstract: A new cardiotonic pentaglycoside with the structure glucoacetyldigoxoside (digoxigenin-β-D-glucosido-acetyltetradigitoxoside) was isolated from the leaves ofDigitalis schischkinii (Ivan.) Werner. Its desacetyl product, glucodigoxoside has also been found in the fraction of most polar glycosides.