Istanbul, Turkey

Yildiz Technical University
Istanbul, Turkey

Yıldız Technical University is a technical university dedicated to engineering science and is one of the most prominent educational institutions in Istanbul, Turkey. The central campus lies within the Beşiktaş district. The new Davutpaşa campus lies within the Esenler district. 10 faculty, 3 vocational schools, and 2 institue. Wikipedia.

Time filter
Source Type

Yildiz Technical University | Date: 2017-04-12

The invention relates to a heating device for a handle, especially an umbrella handle, characterized in that the handle comprises a heating element, especially an electric heating element, preferably a controllable heating element.

Yildiz Technical University | Date: 2017-04-05

A gutter system having a gutter body including a cover surface extending from a rear edge to a forward edge, a return surface extending from a rear edged to a forward edge, and a channel portion including a rear wall, a forward wall and a channel portion therebetween whereby the channel portion defines a collection chamber. The cover surface forward edge and the return surface forward edge meet at a curved wicking edge. The return surface rear edge is connected to an upper edge of the rear wall and the forward wall terminates at an upper edge spaced from the wicking edge to define a water receiving gap.

The present invention relates to a new type of inorganic coordination compound dyes having advanced technology optical, electronic and medical characteristics and relates to production of these dyes by means of new synthesis methods. The present invention relates to dyes which are metal (M: Li, Na, K, Mg, Ca, Sr, Ba, Ti, Zr, V, Cr, Mo, Mn, Re, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, Se, Te) complexes of aromatic macrocyclic compounds of the type Phtalocyanine (Pc), Naphtalocyanine (Nc), Porphyrazine (Pz), Porphyrine (Pr), sub-Phtalocyanine (subPc), sub-Naphtalocyanine (subNc), sub-Porphyrazine (subPz), sub-Porphyrine (subPr), and relates to the synthesis of these complexes and derivatives. The subject matter dyes can be used in solar cell photovoltaic (PV) panels, in OLEDS which are organic structured light emitting diodes, in polymers, in textile and in photodynamic therapy PDT applications. Moreover, industrial applications are possible which depend on strong fluorescence characteristics.

In this study, performance analyses of a gas turbine with two intercoolers and two re-heaters based on energetic, exergetic and ecological concepts such as power, power density, second-law efficiency (exergy efficiency), exergy destruction, ecological coefficient of performance (ECOP) and effective ecological power density (EFECPOD). The effects of turbine design parameters such as turbine speed, air mass flow rate, equivalence ratio, pressure ratio, turbine diameter, turbine length, heat transfer coefficient, residual gas fraction, turbine wall temperature, inlet pressure and inlet temperature on the performance characteristics have been investigated by taking temperature-dependent specific heats and heat transfer losses into consideration. © 2017 Elsevier Ltd

Simsek M.,Yildiz Technical University
Composite Structures | Year: 2010

Vibration of a functionally graded (FG) simply-supported beam due to a moving mass has been investigated by using Euler-Bernoulli, Timoshenko and the third order shear deformation beam theories. The material properties of the beam vary continuously in the thickness direction according to the power-law form. The system of equations of motion is derived by using Lagrange's equations. Trial functions denoting the transverse, the axial deflections and the rotation of the cross-sections of the beam are expressed in polynomial forms. The constraint conditions of supports are taken into account by using Lagrange multipliers. In this study, the effects of the shear deformation, various material distributions, velocity of the moving mass, the inertia, Coriolis and the centripetal effects of the moving mass on the dynamic displacements and the stresses of the beam are discussed in detail. To validate the present results, the dynamic deflections of the beam under a moving mass are compared with those of the existing literature and a comparison study for free vibration of an FG beam is performed. Good agreement is observed. The results show that the above-mentioned effects play a very important role on the dynamic responses of the beam and it is believed that new results are presented for dynamics of FG beams under moving loads which are of interest to the scientific and engineering community in the area of FGM structures. © 2009 Elsevier Ltd. All rights reserved.

Simsek M.,Yildiz Technical University
Nuclear Engineering and Design | Year: 2010

In this paper, fundamental frequency analysis of functionally graded (FG) beams having different boundary conditions is analyzed within the framework of the classical, the first-order and different higher-order shear deformation beam theories. The material properties of the beams vary continuously in the thickness direction according to the power-law form. Two types of formulation are developed. In the first formulation, total bending rotation measured on the beam middle surface is taken as unknown function whereas the shear rotation measured on the beam middle surface is taken as unknown function in the second formulation. The frequency equation is obtained by using Lagrange's equations and the boundary conditions of beams are satisfied with Lagrange multipliers. The unknown functions denoting the axial and the transverse deflections, the bending and the shear rotations of the cross-section of the beam are expressed in the polynomial form. In this study, the effects of slenderness ratio, material variations, the different formulations and the beam theories on the fundamental frequencies are examined. It is believed that the tabulated results will be a reference with which other researchers can compare their results. © 2009 Elsevier B.V. All rights reserved.

Ayat B.,Yildiz Technical University
Energy | Year: 2013

Wave energy potential of the Eastern Mediterranean Sea Basin was assessed and characterized. Wave fields obtained from 3rd generation spectral wave model for years 1994-2009 by using wind data from European Center for Medium-Range Weather Forecasts (ECMWF) were used in order to calculate the wave powers. Wave model was calibrated using the wave measurements conducted at three different stations. Wave model simulated the wave characteristics such as significant wave heights (Hs) and mean wave periods (Tm) with high accuracy. Wave power atlas was generated based on 15-year time-averaged wave data. Also wave power roses and distribution tables in means of periods and heights for different regions were presented. Mean wave power found to be below 2kW/m along the coasts of the whole model area. The most energetic coast of the Southern Mediterranean Basin is Egyptian coastlying between Nile Delta and the Libya border with a potential of above 4kW/m. Some regions along the coasts of some Greek Islands also have potential above 4kW/m within the Aegean Sea Basin. The eastern part of the model area is found to be the least energetic. The most energetic sea states have significant wave heights between 1 and 4m and wave energy periods between 4 and 8s. Seasonal trends were also investigated in this study. The mean wave power in winter is roughly 2 times larger than annual mean. © 2013 Elsevier Ltd.

Simsek M.,Yildiz Technical University
Composites Part B: Engineering | Year: 2014

In this paper, a non-classical beam model based on the Eringen's nonlocal elasticity theory is proposed for nonlinear vibration of nanobeams with axially immovable ends. This non-classical (nonlocal) beam model incorporates the length scale parameter (nonlocal parameter) which can capture the small scale effect. The Hamilton's principal is employed to derive the governing equations and the related boundary conditions together with Euler-Bernoulli beam theory and the von-Kármán's nonlinear strain-displacement relationships. An approximate analytical solution is obtained for the nonlinear frequency of the nanobeam by utilizing the Galerkin method and He's variational method. In the numerical results, the ratio of nonlinear frequency to linear frequency is presented for three different boundary conditions. The effect of nonlocal parameter on the nonlinear frequency ratio is examined. Also, some illustrative examples are also presented to verify the present formulation and solutions. Good agreement is observed. These results can be used as benchmark for future studies. © 2013 Elsevier Ltd. All rights reserved.

In the present manuscript, a non-classical beam theory is developed for the static and nonlinear vibration analysis of microbeams based on a three-layered nonlinear elastic foundation within the framework of the modified couple stress theory and Euler-Bernoulli beam theory together with the von-Kármán's geometric nonlinearity. This non-classical beam model incorporates the length scale parameter which can account for the small size effect. By using the Hamilton's principle, the equations of motion and the boundary conditions of the problem are derived. The nonlinear partial differential equation governing the motion of the system is reduced to the nonlinear ordinary differential equation with the help of the Galerkin discretization technique. He's variational method is then applied for the first time to obtain approximate analytical expressions for the nonlinear frequency of the microbeams with pinned-pinned and clamped-clamped end conditions. Static analysis is also performed for uniformly distributed load. Some illustrative numerical examples are presented in order to investigate the influences of the length scale parameter and the stiffness coefficients of the nonlinear foundation on the static deflection and the ratio of nonlinear frequency to linear frequency (the nonlinear frequency ratio). Comparison studies are also performed to verify the present formulation and solutions. Close agreement is observed. © 2014 Elsevier Ltd.

The use of ethanol-diesel blends in diesel engines without any modifications negatively affects the engine performance and NOx emissions. However, steam injection method decreases NOx emissions and improves the engine performance. In this study, steam injection method is applied into a single cylinder, four-stroke, direct injection, naturally aspirated diesel engine fueled with ethanol-diesel blend in order improve the performance and NOx emissions by using two-zone combustion model for 15% ethanol addition and 20% steam ratios at full load condition. The results obtained are compared with conventional diesel engine (D), steam injected diesel engine (D + S20), diesel engine fueled with ethanol-diesel blend (E15) and steam injected diesel engine fueled with ethanol-diesel blend (E15 + S20) in terms of performance and NO emissions. The results showed that as NO emissions considerably decrease the performance significantly increases with steam injection method. © 2013 Elsevier Ltd. All rights reserved.

Loading Yildiz Technical University collaborators
Loading Yildiz Technical University collaborators