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Articles 17851 - 17880 of 18793
Full-Text Articles in Entire DC Network
Strontium Isotopic And Micropalaeontological Dating Used To Help Redefine The Stratigraphy Of The Neotectonic Hatay Graben, Southern Turkey, Sarah J. Boulton, Alastair H. F. Robertson, Robert M. Ellam, Ümi̇t Şafak, Ulvi̇ Can Ünlügenç
Strontium Isotopic And Micropalaeontological Dating Used To Help Redefine The Stratigraphy Of The Neotectonic Hatay Graben, Southern Turkey, Sarah J. Boulton, Alastair H. F. Robertson, Robert M. Ellam, Ümi̇t Şafak, Ulvi̇ Can Ünlügenç
Turkish Journal of Earth Sciences
In this paper we report for the Hatay Graben, new micropalaeotology, the first strontium dating and new sedimentology. The previous lack of a modern systematic stratigraphy was problematic for the study of the Hatay region. With the new data combined with the existing literature we evaluate and redefine the lithostratigraphy following international standards. The focus of this paper is on the Neogene cover rocks that record the transition from a regional carbonate shelf environment during Palaeocene to Eocene times, through late-stage continental collision, to recent continental rift tectonics that were initiated in the Middle Miocene and continue to operate to …
The Nature Of Medical Evidence And Evidence-Based Practice, John A. Murie
The Nature Of Medical Evidence And Evidence-Based Practice, John A. Murie
Turkish Journal of Medical Sciences
No abstract provided.
A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇
A Critical Review On Electromagnetic Precursors And Earthquake Prediction, Levent Sevgi̇
Turkish Journal of Electrical Engineering and Computer Sciences
Seismo-electromagnetic precursory-based earthquake prediction studies are criticized in terms of their scientific content, problem complexity, signal excitation and propagation, causal relations with earthquakes, and public awareness and expectations. One aim is to trigger a new debate on this hot topic in the Electromagnetic Society.
New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska
New Method For Investigation Of Dynamic Parameters Of Thermoelectric Modules, Raşi̇t Ahiska
Turkish Journal of Electrical Engineering and Computer Sciences
Precise calculation of parameters of thermoelectric modules and thermoelectric devices under operating conditions by present methods is very difficult. In this study, a new method is developed to calculate all parameters of thermoelectric modules. This new method makes it possible to determine the dynamic parameters of a real thermoelectric module operated under different working regimes. Measurement of thermoemf created by an operating module is the basis of this new method. An unloaded thermoelectric module, whose dynamic output parameters are necessary in the design of a medical helmet for the cooling of brain, has been investigated using this new method. A …
Data Mining And Costas Arrays, Konstantinos Drakakis
Data Mining And Costas Arrays, Konstantinos Drakakis
Turkish Journal of Electrical Engineering and Computer Sciences
Costas arrays are used in RADAR (and SONAR) engineering to represent frequency-hopping patterns that optimize the RADAR's performance. In this work, using all available Costas arrays up to and including order 26, as well as data mining techniques, we investigate how the Costas property and the balance of signs in the difference triangle of a permutation are related. Our conclusion is that there is sufficient evidence to believe that the mechanism responsible for the formation of Costas arrays changes from low to high orders.
Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba
Offline Signature Verification Using Graph Matching, Ibrahim S. I. Abuhaiba
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we present a simple and effective signature verification method that depends only on the raw binary pixel intensities and avoids using complex sets of features. The method looks at the signature verification problem as a graph matching problem. The method is tested using genuine and forgery signatures produced by five subjects. An equal error rate of 26.7% and 5.6% was achieved for skilled and random forgeries, respectively. A positive property of our algorithm is that the false acceptance rate of random forgeries vanishes at the point of equal false rejection and skilled forgery false acceptance rates. Keeping …
Cover And Contents
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Aggregation, Foraging, And Formation Control Of Swarms With Non-Holonomic Agents Using Potential Functions And Sliding Mode Techniques, Veysel Gazi̇, Bariş Fi̇dan, Y. Si̇nan Hanay, İlter Köksal
Aggregation, Foraging, And Formation Control Of Swarms With Non-Holonomic Agents Using Potential Functions And Sliding Mode Techniques, Veysel Gazi̇, Bariş Fi̇dan, Y. Si̇nan Hanay, İlter Köksal
Turkish Journal of Electrical Engineering and Computer Sciences
In this article we consider the aggregation, foraging, and formation control of swarms whose agents are moving in 2-dimensions with non-holonomic unicycle agent dynamics. We approach these problems using artificial potentials and sliding mode control. The main contribution is extension of the recent results (mainly for aggregation) in the literature based on a similar approach for simple integrator agent dynamics models to a significantly more realistic and more difficult setting with non-holonomic unicycle agent dynamics models. In particular, we design continuous-time control schemes via a constructive analysis based on artificial potential functions and sliding mode control techniques. The effectiveness of …
Using Angle Of Arrival (Bearing) Information For Localization In Robot Networks, Tolga Eren
Using Angle Of Arrival (Bearing) Information For Localization In Robot Networks, Tolga Eren
Turkish Journal of Electrical Engineering and Computer Sciences
In this paper, we consider using angle of arrival information (bearing) for localization in robot networks. The essential property we require in this paper is that a node can infer heading information from its neighbors. We address the uniqueness of network localization solutions by the theory of globally rigid graphs. We show that while the parallel rigidity problem for formations with bearings is isomorphic to the distance case, the global rigidity of the formation is simpler (in fact identical to the simpler rigidity case) for a network with bearings, compared to formations with distances. We provide the conditions of localization …
Cover And Contents
Turkish Journal of Electrical Engineering and Computer Sciences
No abstract provided.
Study Of The Warranty Cost Model For Software Reliability With An Imperfect Debugging Phenomenon, D.R. Prince Williams
Study Of The Warranty Cost Model For Software Reliability With An Imperfect Debugging Phenomenon, D.R. Prince Williams
Turkish Journal of Electrical Engineering and Computer Sciences
Software reliability is one of the most important characteristics of software quality. Its measurement and management technologies employed during the software life-cycle are essential for producing and maintaining quality/reliable software systems. Herein, we discuss a modified approach to calculating the delivery cost of a software product, when warranty is to be provided, with an imperfect debugging phenomenon. Unlike existing cost models, here the strategy was to consider maintenance support given to the customer with an imperfect debugging phenomenon. The optimal release time can be calculated for various reliability levels by minimizing the cost. The delivery cost, reliability of the software …
New Diterpenoids From The Aerial Parts Of Salvia Pilifera, Ufuk Kolak
New Diterpenoids From The Aerial Parts Of Salvia Pilifera, Ufuk Kolak
Turkish Journal of Chemistry
Three new diterpenoids, piliferol (2\alpha, 20-dihydroxy-12-oxo- abieta-9(11),13-dien-8,20-ether) (1), salvipiliferol (2\alpha, 10\beta -dihydroxy-12-oxo-norabieta-9(11),13-dien) (2), and piliferalactone (2\alpha ,8-dihydroxy-12-oxo-abieta-9(11),13-dien-20-oic acid-8,20-lactone) (3), together with 7 known compounds, ursolic acid, oleanolic acid, betulinic acid, \alpha -amyrin, lupeol, \beta -sitosterol, and pectolinarigenin, have been isolated from the aerial parts of an endemic Salvia species, S. pilifera. Their structures were elucidated by spectral (UV, IR, 1D-, and 2D-NMR, and HRMS) methods.
Development Of A New Set Of Additive Parameters For The Estimation Of Geometrical Distortion Of Cycloalkanes From C-13 Nmr Chemical Shifts, Emad A. S. Al-Hyali
Development Of A New Set Of Additive Parameters For The Estimation Of Geometrical Distortion Of Cycloalkanes From C-13 Nmr Chemical Shifts, Emad A. S. Al-Hyali
Turkish Journal of Chemistry
A previous model for the calculation of C-13 chemical shifts is modified by replacement of 3 parameters representing the p-character of carbon atom in cyclic systems with a single parameter aiming for the development of a new set of parameters with a wide range of application for the calculation of C-13 NMR chemical shifts. The considered systems are cyclohexanes, trans decalins, and a number of hypothetical polycyclic 6-member ring hydrocarbons. The developed parameters include a combination of quantum mechanical and statistical methods. They are based on 2 factors: through bond (electronic) effect represented by the partial electronic charge on the …
Activation Of Light Alkanes On Pure And Fe And Al Doped Silica Clusters: A Density Functional And Oniom Study, Mehmet Ferdi̇ Fellah, Işik Önal
Activation Of Light Alkanes On Pure And Fe And Al Doped Silica Clusters: A Density Functional And Oniom Study, Mehmet Ferdi̇ Fellah, Işik Önal
Turkish Journal of Chemistry
C-H bond activation was studied by use of density functional theory (DFT) and ONIOM calculations as implemented in Gaussian 2003 at the B3LYP level utilising 6-31G* as the basis set for Si, Al, and Fe atoms and 3-21G** as the basis set for O and H atoms. Relative energy profiles were determined for pure silica modeled by a Si_7O_{21} cluster and Fe and Al doped silica clusters via coordinate driving calculations. The activation barriers for C-H bond activation of methane and ethane decrease with the substitution of Fe on the silica surface, which theoretically demonstrates a favorable effect of Fe …
A Mechanistic Approach To Elucidate Ethanol Electro-Oxidation, Ni̇yazi̇ Alper Tapan
A Mechanistic Approach To Elucidate Ethanol Electro-Oxidation, Ni̇yazi̇ Alper Tapan
Turkish Journal of Chemistry
In order to elucidate the mechanism of ethanol oxidation, a simple cylindrical diffusion-surface reaction was developed on a platinum disk electrode. An ethanol electro-oxidation mechanism was proposed, in which electrochemical reactions proceed without adsorption of any electro-oxidation products (C2 type) on the surface. After the simulation of the proposed mechanism, it was seen that the model can explain ethanol electro-oxidation behavior without any surface CO formation. The simulation of the mechanism indicated that the formation of acetaldehyde through the oxidation of bulk ethanol is the rate determining step between 0.6 and 0.75 V vs. RHE. After 0.75 V vs. RHE, …
Direct Formation Of H_2o_2 From H_2 And O_2, Meltem Yildiz, Ayşe Ni̇lgün Akin
Direct Formation Of H_2o_2 From H_2 And O_2, Meltem Yildiz, Ayşe Ni̇lgün Akin
Turkish Journal of Chemistry
The direct combination of hydrogen and oxygen to form hydrogen peroxide in liquid media with prepared catalysts was carried out in a slurry reactor at atmospheric pressure and room temperature. An O_2/H_2 ratio of 2:1 with a 50 mL/min flow rate was used in these experiments. Catalyst activity measurements were tested by the iodometric titration method using KMnO_4. The results are discussed based on the effects of support material, catalyst preparation method, reaction time, and medium (type of halide and acid) on hydrogen peroxide yield in direct oxidation of hydrogen to produce hydrogen peroxide. Our results showed that the catalytic …
Kinetics Of Synthesis Of Isobutyl Propionate Over Amberlyst-15, Ali̇me İzci̇, Hali̇t Levent Hoşgün
Kinetics Of Synthesis Of Isobutyl Propionate Over Amberlyst-15, Ali̇me İzci̇, Hali̇t Levent Hoşgün
Turkish Journal of Chemistry
The esterification of propionic acid with isobutanol in the presence of Amberlyst-15 as a catalyst was studied. Isobutyl propionate synthesized in this reaction has the fragrance of rum and is used in the food industry. The experiments were carried out in a stirred batch reactor at temperatures from 318 K to 348 K. As a solvent, 1,4 dioxan was used. The effects of the amount of catalyst used, the reaction time, the stirring speed, and the reaction temperature on the synthesis of isobutyl propionate were investigated. It was observed that solid-liquid external mass transfer resistance resulting from various stirring speeds …