Browsing by Author "Umul, Yusuf Ziya"

Now showing 1 - 20 of 113

Citation - WoS: 2
Citation - Scopus: 1
Airy-Type Relativistic Matter Wave
(Elsevier Gmbh, 2021) Umul, Yusuf Ziya
A new relativistic Airy-type matter wave is introduced as a solution of the kinetic energy based wave equation. The parametric solution of the related differential equation is obtained. The total energy and momentum of the relativistic particle are derived by using a Bohmian type of decomposition of the kinetic energy based equation. The acceleration of the particle is also evaluated. The behavior of the matter wave is investigated numerically.
Citation - WoS: 1
Citation - Scopus: 1
Application of the Method of Transition Boundary To the Half-Planes With Mixed Boundary Conditions
(Elsevier Gmbh, 2020) Umul, Yusuf Ziya
The scattering problems of waves by soft-hard and hard-soft half-planes are investigated by the method of transition boundary. The functional values at the transition boundaries are found to be identical to the ones for the soft and hard half-screens. It is shown that the factorization process should be applied by also taking into account the boundary conditions besides the principle of reciprocity. The exact diffracted field expressions are obtained for both of the half-planes.
Babinet's principle in the Fraunhofer diffraction by a finite thin wire
(Elsevier GMBH, 2011) Umul, Yusuf Ziya
The scattered waves by a thin finite wire are evaluated by using the Rayleigh-Sommerfeld integral in the Fraunhofer approximation. The scattered fields by the complementary thin wire are also obtained with the aid of the Babinet's principle. The scattering integrals are evaluated directly. It is shown that Babinet's principle holds excellently for this problem. The scattered fields are examined numerically
Citation - WoS: 6
Citation - Scopus: 8
Babinet's Principle in the Fraunhofer Diffraction by a Finite Thin Wire
(Elsevier Gmbh, Urban & Fischer verlag, 2011) Umul, Yusuf Ziya
The scattered waves by a thin finite wire are evaluated by using the Rayleigh-Sommerfeld integral in the Fraunhofer approximation. The scattered fields by the complementary thin wire are also obtained with the aid of the Babinet's principle. The scattering integrals are evaluated directly. It is shown that Babinet's principle holds excellently for this problem. The scattered fields are examined numerically. (C) 2010 Elsevier GmbH. All rights reserved.
Citation - WoS: 4
Citation - Scopus: 4
Beam Diffraction by a Resistive Half-Plane
(Optical Soc Amer, 2015) Umul, Yusuf Ziya
The scattering of a Gaussian beam by a resistive half-screen is investigated. Far-field approximation is used in evaluation of geometrical optics and diffracted waves. The uniform expression of the diffracted waves by the resistive half-plane, which was found with the Sommerfeld-Maliuzhinets method, is obtained. The scattered fields for the case of the beam incidence are evaluated with the technique of a complex point source. The resultant wave expressions are examined numerically. (C) 2015 Optical Society of America
Citation - WoS: 4
Citation - Scopus: 4
Boundary Diffraction Wave Theory Approach To Corner Diffraction
(Springer, 2019) Umul, Yusuf Ziya
The scattering process of plane waves by a discontinuous edge contour is studied with the three dimensional boundary diffraction wave theory. The edge and corner diffracted fields are obtained from the stationary phase and edge point evaluations of the line integral. A new corner diffraction coefficient is derived. The behaviors of the uniform edge and corner diffracted waves are investigated numerically.
Citation - WoS: 5
Citation - Scopus: 5
Boundary Diffraction Wave Theory of Junctions Between Two Surfaces With Different Face Impedances
(Elsevier Sci Ltd, 2012) Umul, Yusuf Ziya
The line integral of the boundary diffraction wave theory is derived for the diffraction process of waves by a junction between two surfaces with different face impedances. The exact solution of Maliuzhinets is used with this aim. The resultant integral is applied to the diffraction of waves by a circular junction between two impedance surfaces. The results are examined numerically. (C) 2011 Elsevier Ltd. All rights reserved.
Citation - WoS: 1
Citation - Scopus: 1
Boundary Diffraction Wave Theory of Resistive Surfaces With Edge Discontinuities
(Elsevier, 2011) Umul, Yusuf Ziya
The line integral of the boundary diffraction wave theory is derived by considering the exact diffracted fields of a resistive half-plane. The line integral is generalized for arbitrary resistive surface with edge discontinuity. The method is applied to the diffraction problem of waves by a convex resistive spherical reflector and the resultant field expressions are investigated numerically. (C) 2011 Elsevier B.V. All rights reserved.
Comparison of physical optics integral and exact solutions for cylinder problem
(2003) Umul, Yusuf Ziya; Yengel, Emre; Aydın, Ayhan
The sound source composition of the urban sound environment varies depending on the geography and socio-cultural context. Current sound taxonomies in the literature categorize urban sound sources by their source types (e.g., human-made, natural, electromechanical) and respective semantic attributes. This study aims to add another taxonomical layer to the existing urban sound source categorization methods. The additional layer is a recently proposed sound source classification framework (CLIC). The CLIC framework identifies sound sources based on their Diegesis and Intention parametric attributes. The former parametric attribute, diegesis, was derived from film sound design. The geographical and socio-cultural context of the built environment can be considered as its narrative; hence, every event that happens within the functional context can be called diegetic, while the events that do not belong to that specific place can be called nondiegetic. The latter parametric attribute, intention, was derived from product design. One of the prominent sound source categorization methods in product sound design is to group the product emitted sounds as consequential and intentional. Combining these two parametric attributes with the existing taxonomies, the CLIC framework outputs a place-specific design guideline, clearly dictating the actions a sound designer should take. The two parametric attributes group the sound sources under four distinct areas, which dictates the degree of influence of designers on the specific sound source. The four zones are defined as the creation zone, limitation zone, isolation zone, and control zone. Each zone dictates step-by-step sound design instructions for the sound designer. This study consists of two main phases: field recordings and web-based listening tests. The sound sources present in the urban sound environment were identified in the field recordings phase. Later, in the web-based listening tests phase, the identified sound sources were evaluated based on the CLIC framework, and hence, their respective zones on the model were identified. The outcomes of the study propose clear step-by-step design guidelines and present action suggestions for environmental sound designers.
Citation - WoS: 6
Citation - Scopus: 7
Diffraction by a Planar Junction Between Resistive and Perfect Electromagnetic Conductor Half-Screens
(Elsevier Gmbh, 2019) Umul, Yusuf Ziya
The interaction of plane electromagnetic waves by a planar junction between resistive and perfect electromagnetic conductor half-planes is investigated. First of all the initial waves for a whole resistive plane is evaluated. Then the scattered geometric optics fields are obtained from the difference of the total geometric optics and initial waves. The diffracted fields are evaluated with the aid of a relation between the scattered geometric optics and diffraction fields at the transition boundaries. It is found that the interaction between the two half-screens occur only for the z-polarized electric fields.
Citation - WoS: 1
Citation - Scopus: 1
Diffraction by an Anomalously Perfect Reflecting Metasurface Half-Plane
(Elsevier Gmbh, 2020) Umul, Yusuf Ziya
The scattering process of plane waves by a half-plane, composed of anomalously perfect reflecting surfaces, is investigated. The solution of the problem is obtained in an original way. The boundary condition of the problem is also taken into account in the construction of the edge diffracted field. The limiting case of the problem is the diffraction of waves by a perfect electric conductor half plane. The obtained field expression are analyzed numerically.
Citation - WoS: 2
Citation - Scopus: 3
Diffraction by an Interface Between Perfect Electromagnetic Conductor and Conductive Surfaces
(Elsevier Gmbh, 2021) Umul, Yusuf Ziya
The interaction of electromagnetic plane waves by a planar interface between conductive and perfect electromagnetic conductor half-planes is investigated. The method of transition boundary is used for the solution of the problem. The geometry, under consideration, is divided into two parts by using a relation, obtained for a perfect electromagnetic conductor half-plane. After obtaining the diffracted fields for sub-problems, they are combined into a single field for the coand cross-polarized waves. The behaviors of the total field and its components are analyzed numerically.
Citation - WoS: 2
Citation - Scopus: 2
Diffraction by Material Half-Planes for Grazing Incidence
(Elsevier Gmbh, Urban & Fischer verlag, 2018) Umul, Yusuf Ziya
It is shown that the actual solutions of the diffraction problem of waves by material half planes do not reduce to the correct diffracted field expressions for grazing incidence. The correct expressions are obtained for the diffracted waves by resistive and conductive half screens. The case for the impedance half-plane directly emerges in terms of the diffracted fields by the previous two semi-screens. The behaviors of the geometric optics and diffraction waves are investigated numerically. (C) 2017 Elsevier GmbH. All rights reserved.
Diffraction in Time in the Relativistic Domain
(Elsevier Gmbh, 2021) Umul, Yusuf Ziya
The diffraction of matter waves in time is investigated by using the kinetic energy based relativistic wave equation for the quantum shutter problem. The differential equation is solved with the aid of the Fourier integral transform according to the spatial coordinate. A new Green's function is obtained and a scattering integral is composed for the wave function. The boundary condition of the quantum shutter problem is expressed in the kernel of the integral. Two field components are derived by the asymptotic evaluation of the scattering integral. The behavior of the scattered matter waves is studied in the relativistic and non-relativistic domains numerically.
Citation - WoS: 2
Citation - Scopus: 3
Diffraction in Time of an Entangled Non-Relativistic Quantum Particle
(Iop Publishing Ltd, 2021) Umul, Yusuf Ziya
The diffraction process of an entangled non-relativistic quantum particle in time domain is investigated. The scenario consists of two entangled spin-0 particles and a quantum shutter, which is opened at an initial time. The particles are traveling in two opposite sides and expressed with a single wave function. The integral solution of the Schrodinger equation is considered for two particles case. The initial condition is expressed in terms of an entangled wave function. The time-diffracted matter wave is obtained in terms of the Fresnel integral. The effect of the phenomenon of diffraction in time is examined numerically for the entangled system of two particles.
Citation - WoS: 11
Citation - Scopus: 9
Diffraction of Cylindrical Waves by a Perfectly Conducting Half-Screen: a Modified Theory of Physical Optics Solution
(Wiley-blackwell, 2016) Umul, Yusuf Ziya
The scattering problem of waves, radiated by a line source, is investigated by the method of modified theory of physical optics. The solution is obtained for both of the Dirichlet and Neumann boundary conditions. Two dimensional modified theory of physical optics integral is considered, since the problem is symmetric according to one of the spatial coordinates. The scattering integral is directly evaluated and a new function is defined for the scattered fields. The mathematical properties of the function are studied. The total, geometrical optics and diffracted waves are analyzed numerically. (C) 2016 Wiley Periodicals, Inc. View this article online at wileyonlinelibrary.com.
Diffraction of Cylindrical Waves by a Transmissive Half-Plane
(Asme, 2017) Umul, Yusuf Ziya
The scattered acoustic waves by a transmissive half-plane, which is illuminated by a line source, are investigated. The high-frequency diffracted wave expressions are obtained by taking into account a resistive half-screen that is defined in electromagnetics. The uniform diffracted fields are expressed in terms of the Fresnel cylinder functions. The behavior of the waves is compared with the case when the uniform theory of diffraction is considered. The geometrical optics and diffracted fields are examined numerically.
Diffraction of Cylindrical Waves by an Impedance Half-Plane
(Elsevier Gmbh, 2019) Umul, Yusuf Ziya
The reflection coefficient of an impedance half-screen, illuminated by a line source field, is not the same with the one of a half-screen for plane wave incidence. This process also affects the structure of the diffraction coefficient. A new diffracted field should be obtained for the illumination of cylindrical waves. This paper introduces a new diffraction coefficient for the impedance half-plane, fed by cylindrical waves. The total and total geometric optics waves are also derived. The variation of the fields is studied numerically.
Citation - WoS: 4
Citation - Scopus: 5
Diffraction of Electromagnetic Waves by a Planar Interface Between Perfectly Absorbing and Anomalously Transmitting Metasurface Half-Planes
(Elsevier Gmbh, 2019) Umul, Yusuf Ziya
The interaction process of electromagnetic waves by a planar interface between perfectly absorbing and anomalously refracting metasurface half-planes is investigated. First of all, the scattered geometric optics field is obtained from the difference of the total geometric optics and initial waves. The diffracted fields are determined by using a relation between the scattered geometric optics and diffraction waves at the transition boundaries. It consists of the diffraction fields of perfectly absorbing and anomalously refracting metasurface half-screens. The behaviors of the total, total geometric optics and diffracted waves are studied numerically.
Citation - WoS: 2
Citation - Scopus: 2
Diffraction of Electromagnetic Waves by a Resistive Half-Plane in Magneto-Ionic Plasma
(Wiley-v C H verlag Gmbh, 2020) Umul, Yusuf Ziya
The interaction of magnetic polarized electromagnetic wave with a resistive half-plane in magneto-ionic plasma is investigated. The method of transition boundary is used for the evaluation of the diffracted wave. The excitation of surface waves is examined in the medium and their diffracted fields are derived by using the diffraction theory for grazing incidence. The uniform field expressions are obtained with the aid of the uniform theory for evanescent waves. The behaviours of the derived scattered waves are studied numerically.