**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**88

# Search results for: Ahmet Yigit Arabul

##### 88 Providing Energy Management of a Fuel Cell-Battery Hybrid Electric Vehicle

**Authors:**
Fatma Keskin Arabul,
Ibrahim Senol,
Ahmet Yigit Arabul,
Ali Rifat Boynuegri

**Abstract:**

On account of the concern of the fossil fuel is depleting and its negative effects on the environment, interest in alternative energy sources is increasing day by day. However, considering the importance of transportation in human life, instead of oil and its derivatives fueled vehicles with internal combustion engines, electric vehicles which are sensitive to the environment and working with electrical energy has begun to develop. In this study, simulation was carried out for providing energy management and recovering regenerative braking in fuel cell-battery hybrid electric vehicle. The main power supply of the vehicle is fuel cell on the other hand not only instantaneous power is supplied by the battery but also the energy generated due to regenerative breaking is stored in the battery. Obtained results of the simulation is analyzed and discussed.

**Keywords:**
Electric vehicles,
fuel cell,
battery,
regenerative
braking,
energy management.

##### 87 An Investigation on Hot-Spot Temperature Calculation Methods of Power Transformers

**Authors:**
Ahmet Y. Arabul,
Ibrahim Senol,
Fatma Keskin Arabul,
Mustafa G. Aydeniz,
Yasemin Oner,
Gokhan Kalkan

**Abstract:**

In the standards of IEC 60076-2 and IEC 60076-7, three different hot-spot temperature estimation methods are suggested. In this study, the algorithms which used in hot-spot temperature calculations are analyzed by comparing the algorithms with the results of an experimental set-up made by a Transformer Monitoring System (TMS) in use. In tested system, TMS uses only top oil temperature and load ratio for hot-spot temperature calculation. And also, it uses some constants from standards which are on agreed statements tables. During the tests, it came out that hot-spot temperature calculation method is just making a simple calculation and not uses significant all other variables that could affect the hot-spot temperature.

**Keywords:**
Hot-spot temperature,
monitoring system,
power transformer,
smart grid.

##### 86 Effect of Derating Factors on Photovoltaics under Climatic Conditions of Istanbul

**Authors:**
Bihter Yerli,
Mustafa K. Kaymak,
Ercan İzgi,
Ahmet Öztopal,
Ahmet D. Şahin

**Abstract:**

**Keywords:**
Efficiency,
Derating Factor,
Istanbul,
Photovoltaic.

##### 85 Decomposition of Homeomorphism on Topological Spaces

**Authors:**
Ahmet Z. Ozcelik,
Serkan Narli

**Abstract:**

**Keywords:**
Generalized closed set,
homeomorphism,
gsghomeomorphism,
sgs-homeomorphism.

##### 84 Pre-beneficiation of Low Grade Diasporic Bauxite Ore by Reduction Roasting

**Authors:**
K. Yılmaz,
B. Birol,
M. N. Sarıdede,
E. Yiğit

**Abstract:**

**Keywords:**
Low grade diasporic bauxite,
magnetic separation,
reduction roasting,
separation index.

##### 83 On the Integer Solutions of the Pell Equation x2 - dy2 = 2t

**Authors:**
Ahmet Tekcan,
Betül Gezer,
Osman Bizim

**Abstract:**

Let k ≥ 1 and t ≥ 0 be two integers and let d = k2 + k be a positive non-square integer. In this paper, we consider the integer solutions of Pell equation x2 - dy2 = 2t. Further we derive a recurrence relation on the solutions of this equation.

**Keywords:**
Pell equation,
Diophantine equation.

##### 82 The Pell Equation x2 − Py2 = Q

**Authors:**
Ahmet Tekcan,
Arzu Özkoç,
Canan Kocapınar,
Hatice Alkan

**Abstract:**

**Keywords:**
Pell equation,
solutions of Pell equation.

##### 81 The Diophantine Equation y2 − 2yx − 3 = 0 and Corresponding Curves over Fp

**Authors:**
Ahmet Tekcan,
Arzu Özkoç,
Hatice Alkan

**Abstract:**

**Keywords:**
Diophantine equation,
Pell equation,
quadratic form.

##### 80 The Number of Rational Points on Singular Curvesy 2 = x(x - a)2 over Finite Fields Fp

**Authors:**
Ahmet Tekcan

**Abstract:**

**Keywords:**
Singular curve,
elliptic curve,
rational points.

##### 79 Impact of Fly Ash-Based Geopolymer Modification on the High-Temperature Properties of Bitumen

**Authors:**
Burak Yigit Katanalp,
Murat Tastan,
Perviz Ahmedzade,
Çigdem Canbay Turkyilmaz,
Emrah Turkyilmaz

**Abstract:**

This study evaluated the mechanical and rheological performance of fly ash-based geopolymer at high temperatures. A series of laboratory tests were conducted on neat bitumen and three modified bitumen samples, which incorporated fly ash-based geopolymer at various percentages. Low-calcium fly ash was used as the alumina-silica source. The dynamic shear rheometer and rotational viscometer were employed to determine high-temperature properties, while conventional tests such as penetration and softening point were used to evaluate the physical properties of bitumen. Short-term aging resistance of the samples was assessed using the rolling thin film oven. The results show that geopolymer has a compromising effect on bitumen properties, with improved stiffness, enhanced mechanical strength, and increased thermal susceptibility of the asphalt binder.

**Keywords:**
Bitumen,
geopolymer,
rutting,
dynamic mechanical analysis.

##### 78 The Number of Rational Points on Conics Cp,k : x2 − ky2 = 1 over Finite Fields Fp

**Authors:**
Ahmet Tekcan

**Abstract:**

Let p be a prime number, Fp be a finite field, and let k ∈ F*p. In this paper, we consider the number of rational points onconics Cp,k: x2 − ky2 = 1 over Fp. We proved that the order of Cp,k over Fp is p-1 if k is a quadratic residue mod p and is p + 1 if k is not a quadratic residue mod p. Later we derive some resultsconcerning the sums ΣC[x]p,k(Fp) and ΣC[y]p,k(Fp), the sum of x- and y-coordinates of all points (x, y) on Cp,k, respectively.

**Keywords:**
Elliptic curve,
conic,
rational points.

##### 77 On Submaximality in Intuitionistic Topological Spaces

**Authors:**
Ahmet Z. Ozcelik,
Serkan Narli

**Abstract:**

**Keywords:**
Intuitionistic set; intuitionistic topology;intuitionistic submaximality and mega-connectedness.

##### 76 On Generalizing Rough Set Theory via using a Filter

**Authors:**
Serkan Narlı,
Ahmet Z. Ozcelik

**Abstract:**

**Keywords:**
Rough set,
fuzzy set,
membership function,
knowledge representation and processing,
information theory

##### 75 The Pell Equation x2 − (k2 − k)y2 = 2t

**Authors:**
Ahmet Tekcan

**Abstract:**

**Keywords:**
Pell equation,
solutions of Pell equation.

##### 74 Enhanced Coagulation of Disinfection By-Products Precursors in Porsuk Water Resource, Eskisehir

**Authors:**
Zehra Yigit,
Hatice Inan,
Guven Seydioglu,
Vedat Uyak

**Abstract:**

**Keywords:**
Chlorination,
Disinfection by-products,
DOC,
Enhanced Coagulation,
NOM,
Porsuk,
UV254.

##### 73 Neighbors of Indefinite Binary Quadratic Forms

**Authors:**
Ahmet Tekcan

**Abstract:**

**Keywords:**
Quadratic form,
indefinite form,
cycle,
proper cycle,
right neighbor,
left neighbor.

##### 72 The Challenge of Large-Scale IT Projects

**Authors:**
Ahmet Denker

**Abstract:**

**Keywords:**
Software engineering,
software economics,
project
management,
large-scale projects.

##### 71 The Number of Rational Points on Elliptic Curves y2 = x3 + b2 Over Finite Fields

**Authors:**
Betül Gezer,
Hacer Özden,
Ahmet Tekcan,
Osman Bizim

**Abstract:**

Let p be a prime number, Fpbe a finite field and let Qpdenote the set of quadratic residues in Fp. In the first section we givesome notations and preliminaries from elliptic curves. In the secondsection, we consider some properties of rational points on ellipticcurves Ep,b: y2= x3+ b2 over Fp, where b ∈ F*p. Recall that theorder of Ep,bover Fpis p + 1 if p ≡ 5(mod 6). We generalize thisresult to any field Fnp for an integer n≥ 2. Further we obtain someresults concerning the sum Σ[x]Ep,b(Fp) and Σ[y]Ep,b(Fp), thesum of x- and y- coordinates of all points (x, y) on Ep,b, and alsothe the sum Σ(x,0)Ep,b(Fp), the sum of points (x, 0) on Ep,b.

**Keywords:**
Elliptic curves over finite fields,
rational points on elliptic curves.

##### 70 Positive Definite Quadratic Forms, Elliptic Curves and Cubic Congruences

**Authors:**
Ahmet Tekcan

**Abstract:**

**Keywords:**
Binary quadratic form,
elliptic curves,
cubic congruence.

##### 69 Investigation of the Effect of Phosphorous on the Flame Retardant Polyacrylonitrile Nanofiber

**Authors:**
Mustafa Yılmaz,
Ahmet Akar,
Nesrin Köken,
Nilgün Kızılcan

**Abstract:**

Commercially available poly(acrylonitrile-co-vinyl acetate) P(AN-VA) or poly(acrylonitrile-co-methyl acrylate) P(AN-MA) are not satisfactory to meet the demand in flame and fire-resistance. In this work, vinylphosphonic acid is used during polymerization of acrylonitrile, vinyl acetate, methacrylic acid to produce fire-retardant polymers. These phosphorus containing polymers are successfully spun in the form of nanofibers. Properties such as water absorption of polymers are also determined and compared with commercial polymers.

**Keywords:**
Flame retardant,
nanofiber,
polyacrylonitrile,
phosphorous compound,
membrane.

##### 68 Sliding Mode Based Behavior Control

**Authors:**
Selim Yannier,
Asif Sabanovic,
Ahmet Onat,
Muhammet Bastan

**Abstract:**

**Keywords:**
Autonomous Mobile Robot,
Behavior Based Control,
Fast Local Obstacle Avoidance,
Sliding Mode Control.

##### 67 A Comparative Analysis of the Perceived Bureaucracy in a Turkish State University

**Authors:**
Ahmet C. Kutlu,
Seçkin Polat

**Abstract:**

**Keywords:**
Degree of bureaucratization,
Hall's Organizational
Inventory,
perceived bureaucracy.

##### 66 Elliptic Divisibility Sequences over Finite Fields

**Authors:**
Betül Gezer,
Ahmet Tekcan,
Osman Bizim

**Abstract:**

**Keywords:**
Elliptic divisibility sequences,
singular elliptic divisibilitysequences,
elliptic curves,
singular curves.

##### 65 Some Algebraic Properties of Universal and Regular Covering Spaces

**Authors:**
Ahmet Tekcan

**Abstract:**

Let X be a connected space, X be a space, let p : X -→ X be a continuous map and let (X, p) be a covering space of X. In the first section we give some preliminaries from covering spaces and their automorphism groups. In the second section we derive some algebraic properties of both universal and regular covering spaces (X, p) of X and also their automorphism groups A(X, p).

**Keywords:**
covering space,
universal covering,
regular covering,
fundamental group,
automorphism group.

##### 64 The Number of Rational Points on Elliptic Curves and Circles over Finite Fields

**Authors:**
Betül Gezer,
Ahmet Tekcan,
Osman Bizim

**Abstract:**

**Keywords:**
Elliptic curves over finite fields,
rational points on
elliptic curves and circles.

##### 63 Transferring Route Plan over Time

**Authors:**
Barıs Kocer,
Ahmet Arslan

**Abstract:**

**Keywords:**
genetic algorithms,
transfer learning,
travellingsalesman problem

##### 62 Performance Comparison of a Low Cost Air Quality Sensor with a Commercial Electronic Nose

**Authors:**
Ünal Kızıl,
Levent Genç,
Sefa Aksu,
Ahmet Tapınç

**Abstract:**

**Keywords:**
Air quality,
electronic nose,
environmental quality,
gas sensor.

##### 61 Comparative Performance Analysis of Nonlinearity Cancellation Techniques for MOS-C Realization in Integrator Circuits

**Authors:**
Hasan Çiçekli,
Ahmet Gökçen,
Uğur Çam

**Abstract:**

**Keywords:**
Integrator circuits,
MOS-C realization,
nonlinearity
cancellation,
tunable resistors.

##### 60 A Diagnostic Fuzzy Rule-Based System for Congenital Heart Disease

**Authors:**
Ersin Kaya,
Bulent Oran,
Ahmet Arslan

**Abstract:**

**Keywords:**
Congenital heart disease,
Fuzzy rule-basedclassifiers,
Classification

##### 59 Testing the Relationship between Economic Freedoms and Growth by Panel Causality Application: Case of Middle East Countries

**Authors:**
Ahmet Ay,
Hakan Acet,
Ceyhun Can Özcan

**Abstract:**

Economic freedoms, most emphasized issue in the recent years, are considered to affect economic growth and performance via institutional structure. In this context, a model that includes Turkey and Middle East Countries, and where the effects of economic freedom on growth are examined, was formed. For the groups of countries determined, in the study carried out by using the dataset belonging the period of 2004 - 2009, between economic freedoms and growth, a negative relationship was observed as group. In the sense of individual effects, it was identified that there was a positive relationship in terms of some Middle East Countries and Turkey.

**Keywords:**
Economic Freedoms,
Economic Growth,
Freedoms.