Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Adsorption (2)
- $p$-valent (1)
- $p$-valently colse-to-convex functions (1)
- $p$-valently convex functions (1)
- $p$-valently starlike functions (1)
-
- 3-Diketone; Addition reaction (1)
- 9-dehydronepetalactone ; sesquiterpene; triterpenoids; steroids. (1)
- Acetic anhydride (1)
- Acetylation. (1)
- Activated carbon (1)
- Active Tectonics (1)
- Adjoint. (1)
- Air (1)
- Alloy electrodes (1)
- Almost periodic functionals. (1)
- Amidrazones. (1)
- Amperometric biosensor. (1)
- Analytic (1)
- And Jack's Lemma. (1)
- Antilinear map (1)
- Artificial neural networks (1)
- Augmented graded modules. (1)
- Banach algebra (1)
- Baranadağ quartz monzonite (1)
- Bentonite (1)
- Benzoate complexes; zinc compound; cadmium compound; mercury compound; thermoydnamics. (1)
- Biodegradable polymer (1)
- Biostratigraphy (1)
- Bitopological spaces. (1)
- Black cobalt electrodeposition (1)
Articles 1 - 30 of 220
Full-Text Articles in Physical Sciences and Mathematics
Taxonomic And Paelogeographic Approaches To The Dasyclad Algae In The Upper Jurassic (Kimmeridgian)-Upper Cretaceous (Cenomanian) Peritidal Carbonates Of The Fele (Yassıbel) Area (Western Taurides, Turkey), İsmai̇l Ömer Yilmaz
Turkish Journal of Earth Sciences
In the Fele (Yassıbel) area in the north of Beyşehir Lake in the Western Taurides, Upper Jurassic (Kimmeridgian) - Upper Cretaceous (Cenomanian) peritidal carbonates were studied in detail. In this study, 30 species of dasyclad algae were identified and 3 new Salpingoporella species were identified within the peritidal carbonates. It was determined that they belong to 13 different genera: Acroporella, Actinoporella, Campbelliella, Clypeina, Cylindroporella, Epimastopora, Epimastoporella, Kopetdagaria, Macroporella, Otternstella, Rajkaella, Salpingoporella, and Selliporella. Salpingoporella is the dominant genus. Some of the species are new records for Turkey: Clypeina nigra, Clypeina parasolkani, Otternstella lemmensis, Salpingoporella biokovensis, Salpingoporella circassa, Salpingoporella piriniae, and …
Clinopyroxene Compositions Of The Isotropic Gabbros From The Sarıkaraman Ophiolite: New Evidence On Supra-Subduction Zone Type Magma Genesis In Central Anatolia, Kenan M. Yaliniz, M. Cemal Göncüoğlu
Clinopyroxene Compositions Of The Isotropic Gabbros From The Sarıkaraman Ophiolite: New Evidence On Supra-Subduction Zone Type Magma Genesis In Central Anatolia, Kenan M. Yaliniz, M. Cemal Göncüoğlu
Turkish Journal of Earth Sciences
The Sarıkaraman Ophiolite is one of the least dismembered ophiolitic units of the allochthonous Central Anatolian Ophiolites, which retains its recognizable pseudostratigraphy. The Sarıkaraman Ophiolite is represented in its lowermost part by isotropic gabbros. Within the isotropic gabbro sequence, clinopyroxenes are observed as small, colorless relicts with a cloudy appearance. In most of the samples, they are completely replaced by a successive generation of green to brown amphiboles. Clinopyroxenes display diopsitic to augitic compositions within the range of En 45 Fs 5 Wo 49 to En 50 Fs 9 Wo 41 . They are Ca-rich and Na-poor (Na 2 O
Field, Petrographic And Geochemical Features Of The Baranadağ Quartz Monzonite Of The Central Anatolian Granitoids, Turkey, Nurdan S. Aydin, A. Piril Önen
Field, Petrographic And Geochemical Features Of The Baranadağ Quartz Monzonite Of The Central Anatolian Granitoids, Turkey, Nurdan S. Aydin, A. Piril Önen
Turkish Journal of Earth Sciences
The Baranadağ quartz monzonite is one of the granitioid intrusions of the Central Anatolian Crystalline Complex (CACC) which represents the passive continental margin of the Anatolide-Tauride platform. Medium to coarse-grained Baranadağ quartz monzonites typically include mafic microgranular enclaves and K-feldspar megacrysts and are cut by aplitic dykes representing the youngest magmatic activity of the study area. The intrusion is mainly composed of orthoclase, plagioclase, quartz, hornblende, biotite and clinopyroxene. It displays a slightly alkaline character and relatively well-developed calc-alkaline trend. The metaluminous Baranadağ quartz monzonites show comparable field, petrographic and/or geochemical features with those of the H-type (Hybrid) granitoids of …
Biostratigraphic And Environmental Analysis Of The Upper Jurassic- Lower Cretaceous Carbonate Sequence In The Başoba Yayla Area (Trabzon, Ne Turkey), Kemal Tasli, Erol Özer, Cemi̇l Yilmaz
Biostratigraphic And Environmental Analysis Of The Upper Jurassic- Lower Cretaceous Carbonate Sequence In The Başoba Yayla Area (Trabzon, Ne Turkey), Kemal Tasli, Erol Özer, Cemi̇l Yilmaz
Turkish Journal of Earth Sciences
In the Başoba Yayla (Trabzon, NE Turkey) area, which is located in the Eastern Pontides northern zone, platform carbonates were deposited during the Late Jurassic-Early Cretaceous time in environments varying from intertidal/ supratidal to outer shelf. The carbonate sequence begins with a thick dolomite unit of the Late Jurassic to Early Cretaceous age. The following unit is rich in benthic foraminifers and pelecypoda shells. The foraminiferal assemblage comprising Vercorsella laurentii/camposaurii and Pseudolituonella gavonensis indicates a Late Hauterivian to Early Aptian age for this unit. The Late Aptian-Albian facies is characterized by bioclastic wackestones containing benthic foraminifers typical of outer platform …
Mafic Microgranular Enclaves In The Kozak Granodiorite, Western Anatolia, Cüneyt Akal, Cahi̇t Helvaci
Mafic Microgranular Enclaves In The Kozak Granodiorite, Western Anatolia, Cüneyt Akal, Cahi̇t Helvaci
Turkish Journal of Earth Sciences
Enclaves which are relicts of initial basic magma give important information on the origin and evolution of granitic magmas. The mafic microgranular enclaves from the l-type Kozak pluton are less than 1 m that are located at the margin of pluton and mostly less than 15 cm and are generally in sharp contact with the surrounding granodiorite. In some cases, several enclaves may occur close to each other, but they are not closely clustered to form swarms. Most of the enclaves are ellipsoidal in shape. The largest enclaves are less ellipsoidal with curved boundaries. The mafic microgranular enclaves contain same …
Rock-Forming Nannofossils In Uppermost Jurassic-Lowercretaceous Rock Units Of Northwest Anatolia: Nannoconusand Its Resived Taxonomy, Sevi̇nç Özkan Altiner
Rock-Forming Nannofossils In Uppermost Jurassic-Lowercretaceous Rock Units Of Northwest Anatolia: Nannoconusand Its Resived Taxonomy, Sevi̇nç Özkan Altiner
Turkish Journal of Earth Sciences
Nannoconids have been recorded in a rock-forming quantity in the uppermost Jurassic-Lower Cretaceous rock units in Northwest Anatolia, Turkey. Samples were collected from seventeen stratigraphic sections spanning the calciturbidities of the Yosunlukbayiri Formation and pelagic micrites of the Sogukçam Limestone. Because of rareness and difficulties for extracting of calcareous nannofossil species particularly zone markers in these type lithologies, nannoconids have particular attention in terms of biostratigraphy. Twenty nine species of nannoconids were recorded in the studied samples. Their taxonomy were revised and their stratigraphic ranges were given. The classification of genus Nannoconusis based on the gross morphology of the test, …
Deformation Of Stibnites And Pyrites In The Madsan Antimony Deposit (Niğde, Turkey): Implications For Pressure-Temperatureconditions Of Local Deformation, İlkay Kuşcu, Ayhan Erler
Deformation Of Stibnites And Pyrites In The Madsan Antimony Deposit (Niğde, Turkey): Implications For Pressure-Temperatureconditions Of Local Deformation, İlkay Kuşcu, Ayhan Erler
Turkish Journal of Earth Sciences
The Madsan antimony deposit at the southeastern part of the Niğde province (south-central Turkey) includes a series of epithermal veins hosted by marbles and gneisses. The veins have a simple mineralogy of quartz, calcite, stibnite and pyrite as major constituents, and cinnabar occurs in trace amounts. The deposit experienced a progressive deformation evidenced by a set of textures developed especially in stibnite and pyrite. These are pressure lamellae and annealing as the main textures, and curvature, off-set of pressure lamellae and fracture filling as the textures of minor importance. These were developed in three successive deformation phases. Pressure lamellae represent …
Geology Of The Dereiçi (Şavsat, Artvin) Cu-Pb-Zn Deposits, Mesut Soylu, Ayhan Erler
Geology Of The Dereiçi (Şavsat, Artvin) Cu-Pb-Zn Deposits, Mesut Soylu, Ayhan Erler
Turkish Journal of Earth Sciences
The geological relationships between the rock units in the Dereiçi/Şavsat (Artvin) region and vein-type Cu-Pb-Zn deposits were presented in this paper. The study area comprises the Upper Cretaceous intermediate volcanic rocks and sedimentary rocks, with Post-Eocene dykes of andesitic and diabasic composition. The mineral deposits are classified as (1) Sphalerite-Galena-Chalcopyrite-Pyrite veins (Talatin Madeni, Binektasi and Fikrinin Madeni), (2) milky quartz-Chalcopyrite-Sphalerite-Galena-Pyrite veins and (3) Chalcopyrite-Pyrite veins. The general paragenetic sequence of the mineralizations is observed as quartz I-pyrite-chalcopyrite-sphalerite-galena-quartz II-chalcocite-covellite. The wall rocks are subjected to silicification, sericitic alteration, chloritization and carbonatization.
Along-Strike Discontinuity Of Active Normal Faults And Its Influence On Quaternary Travertine Deposition; Examples From Western Turkey, Zi̇yadi̇n Çakir
Along-Strike Discontinuity Of Active Normal Faults And Its Influence On Quaternary Travertine Deposition; Examples From Western Turkey, Zi̇yadi̇n Çakir
Turkish Journal of Earth Sciences
Detail mapping of active fault zones bounding four travertine masses in the Gediz and Menderes grabens of western Turkey revealed that they are divided into geometric fault segments up to 13 km long. Fissures, supplying the carbonate-rich waters that give rise to the travertines are preferentially developed at the ends of the fault segments or in extensional step-over zones where the offset between the fault strands is about 1 km or more. The deposition of travertines in such structural settings is probably a consequence of the network of fissures supplying the carbonate-rich waters being highly interconnected where extensional strains were …
An Efficient Acetylation Of Primary And Secondary Aliphatic Alcohols With Acetic Anhydride In The Presence Of Graphite Bisulphate, Hasan Seçen, A. Hami̇t Kalpar
An Efficient Acetylation Of Primary And Secondary Aliphatic Alcohols With Acetic Anhydride In The Presence Of Graphite Bisulphate, Hasan Seçen, A. Hami̇t Kalpar
Turkish Journal of Chemistry
In cyclohexane, thirteen examples of primary and secondary aliphatic alcohols were easily converted to the corresponding acetate derivatives within a short time, ranging from 5 min to 2.5 h, and in good yields close to 90%, using acetic anhydride as reagent and graphite bisulphate as an efficient catalyst.
The Effects Of Detergent Pollution On The Corrosion Of Iron And Aluminium, Si̇bel Zor, B. Yazici, M. Erbi̇l
The Effects Of Detergent Pollution On The Corrosion Of Iron And Aluminium, Si̇bel Zor, B. Yazici, M. Erbi̇l
Turkish Journal of Chemistry
The current-potential values were measured with iron or aluminium electrodes in solutions of 3.5% NaCl containing 30, 150, 300 ppm linear alkylbenzene (LAB) and detergents (LAS) at pH8. Polarization resistances (Rp) were determined using the values of current and potentials. The corrosion rates of iron and aluminium were determined in 2 and 4 hour intervals using the Mansfeld-Oldham equation based on the Stern-Geary and Butler-Volmer equations.
Nonextensivity And Quantum Groups, Metin Arik
Nonextensivity And Quantum Groups, Metin Arik
Turkish Journal of Physics
Classical set theory is nonextensive since the mathematical definition of a set excludes the possibility that more than one copy of the same element can be in a set. We show that the description of random sets in terms of an algebra of creation operators and their hermitean conjugates yields an interpretation of the unitary quantum group SU_q(d) as the symmetry associated with the construction of d random sets from a given source set of M=(1-q)^{-1} elements.
Q-Calculus And Irreversible Dynamics On A Hierarchical Lattice, Ayşe Erzan, Ayşe Gorbon
Q-Calculus And Irreversible Dynamics On A Hierarchical Lattice, Ayşe Erzan, Ayşe Gorbon
Turkish Journal of Physics
On a lattice with equal spacing on the logarithmic scale, a momentum operator that respects the asymmetry of this nonlinear lattice yields a kinetics that can be understood in terms of diffusion on an underlying ultrametric space, if one also identifies the cannonical commutator with the time dilation operator. The motion to which this non-conventional kinetics corresponds is irreversible, with an explicit violation of time reversal symmetry resulting from the spreading with time of a probability distribution over a larger and larger volume of the phase space.
A New Formalism For Nonextensive Physical Systems: Tsallis Thermostatistics, Uğur Tirnakli, Fevzi Büyükkiliç, Doğan Demi̇rhan
A New Formalism For Nonextensive Physical Systems: Tsallis Thermostatistics, Uğur Tirnakli, Fevzi Büyükkiliç, Doğan Demi̇rhan
Turkish Journal of Physics
Although Boltzmann-Gibbs (BG) statistics provides a suitable tool which enables us to handle a large number of physical systems satisfactorily, it has some basic restrictions : (i) the range of the microscopic interactions must be small compared to the linear size of the macroscopic systems (short-range interactions) , (ii) the time range of the microscopic memory must be small compared to the observation time (Marcovian processes) and (iii) the system must evolve in an Euclidean-like space-time. In the case of a breakdown in one and/or the others of these restrictions, BG statistics fails. More precisely, the situation could be classified …
Statistical Physics, Neural Networks, Brain Studies, Gerard Toulouse
Statistical Physics, Neural Networks, Brain Studies, Gerard Toulouse
Turkish Journal of Physics
An overview of some aspects of a vast domain, located at the crossroads of physics, biology and computer science is presented: 1) During the last fifteen years, physicists advancing along various pathways have come into contact with biology (computational neurosciences) and engineering (formal neural nets). 2) This move may actually be viewed as one component in a larger picture. A prominent trend of recent years, observable over many countries, has been the establishment of interdisciplinary centers devoted to the study of: cognitive sciences; natural and artificial intelligence; brain, mind and behaviour; perception and action; learning and memory; robotics; man-machine communication, …
Neural Classifiers For Learning Higher-Order Correlations, Marifi Güler
Neural Classifiers For Learning Higher-Order Correlations, Marifi Güler
Turkish Journal of Physics
Studies by various authors suggest that higher-order networks can be more powerful and are biologically more plausible with respect to the more traditional multilayer networks. These architectures make explicit use of nonlinear interactions between input variables in the form of higher-order units or product units. If it is known a priori that the problem to be implemented possesses a given set of invariances like in the translation, rotation, and scale invariant pattern recognition problems, those invariances can be encoded, thus eliminating all higher-order terms which are incompatible with the invariances. In general, however, it is a serious set-back that the …
Ordering Due To Disorder In Frustrated Quantum Magnetic Systems, Taner Yildirim
Ordering Due To Disorder In Frustrated Quantum Magnetic Systems, Taner Yildirim
Turkish Journal of Physics
The phenomenon of order by disorder in frustrated magnetic systems is reviewed. Disorder (thermal or quantum fluctuations) may sometimes give rise to long range ordering in systems with frustration, where one must often consider the selection among classically degenerate ground states which are not equivalent by any symmetry. The lowest order effects of quantum fluctuations in such frustrated systems usually resolves the continues degeneracy of the ground state manifold into discrete Ising--type degeneracy. A unique ground state selection out of this Ising degenerate manifold then occurs due to higher order effects of quantum fluctuations. For systems such as face-centered cubic …
The Renormalization-Group Microscope: The Local Statistical Mechanics Of Heterogeneous Systems, Dicle Yeşi̇lleten, A. Nihat Berker
The Renormalization-Group Microscope: The Local Statistical Mechanics Of Heterogeneous Systems, Dicle Yeşi̇lleten, A. Nihat Berker
Turkish Journal of Physics
Renormalization-group theory is developed to yield all local microscopic thermodynamic densities in heterogeneous systems. Local energy densities and local magnetizations are thus obtained for random-bond systems, random-field systems, and spin-glasses, in two and three dimensions. Different order-disorder mechanisms in these diverse systems, such as chaotic ordering and domain-wall melting, become quantitatively evident.
Experimental Determination Of \Beta And \Gamma Critical Exponents In The Sol-Gel Phase Transition By Using Steady-State Fluorescence Technique, Y. Yilmaz, Ö. Pekcan
Experimental Determination Of \Beta And \Gamma Critical Exponents In The Sol-Gel Phase Transition By Using Steady-State Fluorescence Technique, Y. Yilmaz, Ö. Pekcan
Turkish Journal of Physics
The gelation of methyl methacrylate and ethylene glycol dimethacrylate was studied using the steady-state fluorescence technique. Samples with various crosslinker densities were prepared and sol-gel phase transitions were observed at various temperatures. Percolation theory was employed to interpret the results. For all samples the gel fraction and the average cluster size exponents, \beta and \gamma, were measured and found to be around 0.42 and 1.7 respectively. These values show excellent agreement with theoretical and simulation results.
Assessment Of The Degree Of Mix Of Powder Mixtures, Orhan Vai̇zoğlu
Assessment Of The Degree Of Mix Of Powder Mixtures, Orhan Vai̇zoğlu
Turkish Journal of Physics
The older methods for the determination of the degree of a random mix was solely based on the calculation of a simple standard deviation. Physical characteristics like, density, average particle weight and size of each component was not considered. Therefore, the evaluation, when the state of a random mix is reached, was somewhat superficial. Poole, Taylor, and Wall [1] have derived equations, where the physical characteristics of the components were taken into consideration. By this means, it is possible to calculate, in advance, the theoretical coefficient of variation and the corresponding confidence limits. One can then experimentally follow under which …
Studies On Extremal Segments In Random Sequences, Deniz Ertaş, Yacov Kantor
Studies On Extremal Segments In Random Sequences, Deniz Ertaş, Yacov Kantor
Turkish Journal of Physics
We review our main findings on the size distribution of the largest neutral segments in a sequence of N randomly charged monomers. Upon mapping to one--dimensional random walks (RWs), this corresponds to finding the probability distribution for the size L of the largest segment that returns to its starting position in an N--step RW. Using analytical, exact enumeration, and Monte Carlo methods, we reveal the complex structure of the probability distribution in the large N limit. In particular, the size of the longest neutral segment has a distribution with a square-root singularity at \ell\equiv L/N = 1, an essential singularity …
Diverging Strains Near Threshold: Breakdown Of The Elastic Description Of A Charge Density Wave Model, Muhittin Mungan, Susan N. Coppersmith, Valeri M. Vinokur
Diverging Strains Near Threshold: Breakdown Of The Elastic Description Of A Charge Density Wave Model, Muhittin Mungan, Susan N. Coppersmith, Valeri M. Vinokur
Turkish Journal of Physics
We analyze the strains near threshold in 1-d charge density wave models at zero temperature and strong pinning. We show that in these models local strains diverge near the depinning threshold and characterize the scaling behavior of the phenomenon. This helps quantify when the underlying elastic description breaks down and plastic effects have to be included.
Electron Liquid Beyond The Random Phase Approximation, Mehmet Tomak, Ceyhun Bulutay
Electron Liquid Beyond The Random Phase Approximation, Mehmet Tomak, Ceyhun Bulutay
Turkish Journal of Physics
A deeper understanding of low-dimensional and small-scale electronic systems requires an accurate characterization of the many-electron effects. Based on the electron liquid (EL) model, these many-body effects in the three-dimensional (3D) and two-dimensional (2D) electronic systems are dealt going beyond the random phase approximation within the zero-temperature framework. The dielectric formulation of the many-body problem is recapitulated and the longitudinal dielectric function of the EL is obtained using the self-consistent local-field correction scheme, known as STLS, under a general spin-valley degeneracy. Extensive explicit expressions are provided for the use of other researchers. The performance of this formalism is compared in …
Magnetic Excitations In Random Anisotropic Magnets, İbrahim Avgin
Magnetic Excitations In Random Anisotropic Magnets, İbrahim Avgin
Turkish Journal of Physics
A study is made for the magnetic excitations and their Anderson localization properties for a Heisenberg ferromagnet with random anisotropic fields. The system is assumed to be in a strong applied field so that complete spin alignment is established. The magnetic excitations, i.e., the harmonic spin waves, are computed using coherent-field-anisotropy approximation (a version of coherent potential approximation of the electronic problem). The spin wave shift and damping are calculated using the computed coherent field which is a complex function of energy approximating the random medium as a mean field level. The localizaton of the excitations are calculated by adopting …
Weak Localization In Disordered Two-Dimensional Crystals With Half-Filled Band, E.P. Nakhmedov, T. Kaya
Weak Localization In Disordered Two-Dimensional Crystals With Half-Filled Band, E.P. Nakhmedov, T. Kaya
Turkish Journal of Physics
Effect of subtitutional impurities on electron localization in two dimensional (2D) lattice near the middle of the band is studied. Calculation of density of the electronic states, \rho (\varepsilon ), increases logaritmically in the middle of the band. This singularity in the density of states of noninteracting electron gas on lattice gives rise to anomalous dependencies of thermodynamic quantities on the temperature. The quantum correction to the conductivity of a nonintreracting electron gas due to Umklapp electron--impurity scattering is calculated. This correction to the conductivity is shown to compete with that from the localization corrrection for a Normal scattering process. …
Spectral Broadening Functions, Slavek Rucinski
Spectral Broadening Functions, Slavek Rucinski
Turkish Journal of Physics
Many astrophysical phenomena involving velocity fields produce broadening of spectral lines. Frequently, the cross-correlation function (CCF) is used to extract information about this broadening from segments of high resolution spectra. CCF has become the standard tool for handing extraction of radial-velocity and broadening information from high resolution spectra as it permits integration of information which is common to many spectral lines into one function which is easy to calculate, visualize and interpret. However, it can be argued that this is not the best tool for applications such as determinations of metallicities ([Fe/H]), for finding locations of star spots on active …
Angular Momentum Evolution In Close Late-Type Binaries, Carla Maceroni
Angular Momentum Evolution In Close Late-Type Binaries, Carla Maceroni
Turkish Journal of Physics
Accurate monitoring of the orbital period of late-type close binaries can provide important information on their secular evolution and on the structural changes of their components on very short timescales (i.e. decades). The orbital period turns out to be a powerful tool of investigation: it can be measured to great accuracy even with simple equipments and its change produces an easily detectable cumulative effect over time. This paper focuses on two physical mechanisms that cause orbital periods changes in late type binaries with negligible mass loss from the system: the dynamical evolution due to magnetic braking in tidally locked systems, …
Cyclic Nature Of The Orbital Period Variations Of Some Algol-Type Binaries, Seli̇m O. Selam, Osman Demi̇rcan
Cyclic Nature Of The Orbital Period Variations Of Some Algol-Type Binaries, Seli̇m O. Selam, Osman Demi̇rcan
Turkish Journal of Physics
The long-term period variations of the classical algol-type binaries XZ And, U Cep, \beta Per, RT Per, ST Per and TX UMa were studied by using all available observed times of eclipse minima. The (O-C) diagrams formed by the times of eclipse minima were found to be representable by one or more cyclic variations superimposed on a secular parabolic variation. The secular variations in the orbital periods should be caused by the mass transfer between the component stars and the mass loss from the systems. For our sample of Algol systems, none of the cyclic variations were found caused by …
Short-Period Rs Cvn And W Uma Binaries: How Are They Related?, Frans Van't Veer
Short-Period Rs Cvn And W Uma Binaries: How Are They Related?, Frans Van't Veer
Turkish Journal of Physics
Two groups of late-type very close main sequence binaries, the so-called short-period RS Canum Venaticorum (RS CVn) and W Ursae Majoris (W UMa) systems, are important for the understanding of the structure and evolutionary consequencies of angular momentum loss (AML) resulting from magnetic stellar winds of fast rotating solar type stars. The components of RS CVn stars are close to their Roche lobes, but still detached, whereas W UMa binaries are contact systems; both are rotating fast. One of the crucial problems is trying to answer the question if there is a dynamical relation between the two types of binaries …
Orbital Period Modulation In Chromospherically Active Close Binaries, Cafer İbanoğlu
Orbital Period Modulation In Chromospherically Active Close Binaries, Cafer İbanoğlu
Turkish Journal of Physics
The orbital period changes in some chromospherically active close binaries have been interpreted as a consequence of magnetic activity. At least in two active close binaries a possible relationship between the orbital period modulation and activity cycle was suggested. The existence of a third companion in these binaries has also been proposed. The light-time effect which arises from orbiting around a third-body has been subtracted from all the O-C values and a cyclic change of the orbital period has been obtained. These cyclic changes seem to be connected with the total brightness variations at least in two samples, namely, V471 …