WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article Selection of Optimum Performance Conditions in the Laser-Assisted Turning of Aisi 4340 Hardened Steel Through the Coupling of Entropy/Mcdm Analysis(Springer Heidelberg, 2024) Khatir, Farzad Ahmadi; Modanloo, Vahid; Abedini, Vahid; Akar, Samet; Ghadikolaee, Hossein TalebiThe laser-assisted turning (LAT) process comprises complicated interactions between cutting process parameters and laser heating. These interactions pose a significant challenge for predicting and optimizing surface integrity, even though it is crucial for the success of the process and its adoption as an alternative industrial process. This research employs multi-criteria decision-making (MCDM) approaches to determine the optimal machining conditions. The entropy method was applied to assign weights to the criteria, and the MOORA and TOPSIS techniques were utilized to rank the alternatives. A combination of various machining parameters, including feed, cutting speed, and depth of cut were assumed to be the alternatives (machining conditions). Moreover, the white layer thickness, microhardness, and surface roughness were considered selection criteria. The results demonstrated that all parameters are effective for surface integrity. On the other hand, the properties of surface integrity were greatly impacted by the laser power and feed. Therefore, the factors that most affected the creation of the white layer were the feed (47.26%) and the laser power (22.10%). The most advantageous process parameters for the LAT of AISI 4340 steel were found to be a cutting speed of 240 m/min, a cutting feed of 0.07 mm/rev, a cutting depth of 0.5 mm, and a laser power of 450 W by the MCDM analysis.Article Citation - WoS: 26Citation - Scopus: 26The Geophysical Kdv Equation: Its Solitons, Complexiton, and Conservation Laws(Springer Heidelberg, 2022) Hosseini, K.; Akbulut, A.; Baleanu, D.; Salahshour, S.; Mirzazadeh, M.; Akinyemi, L.The main goal of the current paper is to analyze the impact of the Coriolis parameter on nonlinear waves by studying the geophysical KdV equation. More precisely, specific transformations are first adopted to derive one-dimensional and operator forms of the governing model. Solitons and complexiton of the geophysical KdV equation are then retrieved with the help of several well-established approaches such as the Kudryashov and Hirota methods. In the end, the new conservation theorem given by Ibragimov is formally employed to extract conservation laws of the governing model. It is shown that by increasing the Coriolis parameter, based on the selected parameter regimes, less time is needed for tending the free surface elevation to zero.Article Citation - WoS: 12Citation - Scopus: 17Dynamics of Multi-Point Singular Fifth-Order Lane-Emden System With Neuro-Evolution Heuristics(Springer Heidelberg, 2022) Ali, Mohamed R.; Fathurrochman, Irwan; Raja, Muhammad Asif Zahoor; Sadat, R.; Baleanu, Dumitru; Sabir, ZulqurnainThe objective of the presented communication is to examine and analyze the solutions of nonlinear multi-singular fifth-order Lane-Emden (LE) system for different scenarios by variation of shape factors settled on the equivalent design of the LE equations. The neuro-evolution based stochastic computing is explored for the numerical measures using the artificial neural networks (ANNs) models for the appropriate continuous mapping, while the learning of decision variables is conducted using the integrated meta-heuristic global search of genetic algorithms (GA) hybrid with the local search efficiency of active-set (AS) i.e., ANN-GA-AS scheme. The numerical approach ANN-GA-AS is applied efficiently for the fifth kind of nonlinear LE model and statistical calculations further validate the accuracy, robustness as well as convergence.Article Citation - WoS: 7Citation - Scopus: 6Dynamic Flat-Topped Laser Beam Shaping Method Using Mixed Region Amplitude Freedom Algorithm(Springer Heidelberg, 2022) Arpali, Caglar; Arpali, Serap Altay; Altemimi, Mohammed Fawzi; Alsaka, Dina YaqoobA dynamic beam shaping method is proposed for the generation of flat-top beams (FTBs) in the far field. Using the mixed-region amplitude freedom algorithm, this new method is used to design the required phase distribution encoded on a spatial light modulator for the generation of FTB profiles. The characteristics of these new beam shaping methods are used as beam parameters, such as the laser beam size, the beam intensity of square FTBs, and the root-mean-square error (RMSE). Using our proposed method, the theoretical performance of beam intensity shaping is improved to an RMSE < 0.02 with a minimum number of iterations of phase reconstruction. Using the phase hologram of dynamic beam shaping, theoretical and experimental comparisons of edge steepness and plateau uniformity were established for the square FTBs of variable beam sizes. It is shown that the dynamic beam shaping of FTBs can produce high intensity uniformity in the plateau region with steep edges, which makes it an effective tool, especially for laser machining applications.Article Citation - WoS: 23Citation - Scopus: 21Numerical Solution of a New Mathematical Model for Intravenous Drug Administration(Springer Heidelberg, 2024) Shiri, Babak; Perfilieva, Irina; Baleanu, Dumitru; Alijani, ZahraWe develop and analyze a new mathematical model for intravenous drug administration and the associated diffusion process. We use interval analysis to obtain a system of weakly singular Volterra integral equations over ordinary functions. We then use the operational method based on Chebyshev polynomials for obtaining an approximate solution of the numerical form. We show that for a certain class of fuzzy number valued functions, their generalized Hukuhara derivatives can be reduced to the derivatives of ordinary real-valued functions. By using our approach, we are able to estimate numerical solutions very accurately.Article Citation - WoS: 31Citation - Scopus: 36Beam Wander of Dark Hollow, Flat-Topped and Annular Beams(Springer Heidelberg, 2008) Cil, C. Z.; Eyyuboglu, H. T.Benefiting from the earlier derivations for the Gaussian beam, we formulate beam wander for dark hollow (DH) and flat-topped (FT) beams, also covering the annular Gaussian (AG) beam as a special case. Via graphical illustrations, beam wander variations of these beams are analyzed and compared among themselves and to the fundamental Gaussian beam against changes in propagation length, amplitude factor, source size, wavelength of operation, inner and outer scales of turbulence. These comparisons show that in relation to the fundamental Gaussian beam, DH and FT beams will exhibit less beam wander, particularly at small primary beam source sizes, lower amplitude factors of the secondary beam and higher beam orders. Furthermore, DH and FT beams will continue to preserve this advantageous position all throughout the considered range of wavelengths, inner and outer scales of turbulence. FT beams, in particular, are observed to have the smallest beam wander values among all, up to certain source sizes.Article Citation - WoS: 16Citation - Scopus: 18Multimode Laser Beam Scintillations in Strong Atmospheric Turbulence(Springer Heidelberg, 2019) Baykal, Yahya; Gercekcioglu, HamzaMultimode laser beam scintillation index is formulated at the origin of the receiver plane (on-axis) in strong atmospheric turbulence using the modified Rytov method. Variations of the scintillation index against the turbulence strength and the size of the multimode laser beam are reported for various multimode laser beam contents. It is found that when the multimode content is increased, i.e. when the laser beam contains more modes, and when the multimode content is composed of modes with larger mode numbers, the scintillations tend to reduce in strong atmospheric turbulence. Thus, to achieve smaller intensity fluctuations in atmospheric wireless optics communication systems having long link lengths or operating in strong turbulence, use of multimode laser beams can be recommended.Article Citation - WoS: 5Citation - Scopus: 5Analysis and Testing of a Contraction-And Micromixer for Micromilled Microfluidics(Springer Heidelberg, 2017) Yildirim, EnderIn this paper, numerical analysis and experimental investigation of a micromixer, which was specifically designed for microfluidic devices fabricated by micromilling, is presented. The mixer is composed of series of contractions and expansions in zigzag arrangement along a mixing channel. Mixers, fabricated by micromilling on polymethylmethacrylate (PMMA), were tested with %0.1 Ponceau 4R red food dye solution and distilled water. According to experiment results, over 70% mixing efficiency could be obtained for the flows with Reynolds number (Re) greater than 40. It was also numerically shown that by increasing the number of successive contractions and expansions, it could be possible to achieve over 80% mixing efficiency when Re = 55 for the species with diffusion coefficient of 5 x 10(-9) m(2)/s. Although the micromixer was specifically designed for micromilling, it is expected that the mixer can be useful in any microfluidic device fabricated by any other technique.Article Citation - WoS: 14Citation - Scopus: 18Oscillation of Even Order Nonlinear Delay Dynamic Equations on Time Scales(Springer Heidelberg, 2013) Mert, Raziye; Peterson, Allan; Zafer, Agacik; Erbe, LynnOne of the important methods for studying the oscillation of higher order differential equations is to make a comparison with second order differential equations. The method involves using Taylor's Formula. In this paper we show how such a method can be used for a class of even order delay dynamic equations on time scales via comparison with second order dynamic inequalities. In particular, it is shown that nonexistence of an eventually positive solution of a certain second order delay dynamic inequality is sufficient for oscillation of even order dynamic equations on time scales. The arguments are based on Taylor monomials on time scales.Article Citation - WoS: 10Citation - Scopus: 12Scintillation Behavior of Cos, Cosh and Annular Gaussian Beams in Non-Kolmogorov Turbulence(Springer Heidelberg, 2012) Eyyuboglu, H. T.For a non-Kolmogorov spectrum, scintillation aspects of cos, cosh and annular Gaussian beams are investigated. The appropriate mathematical formulation is developed, the derived scintillation index is evaluated and its variation is plotted in graphs. We find that, when the values of the power coefficient of the spectrum are just above 3, low scintillation is encountered, then as the power coefficient is increased, rises will occur with a peak being reached around 3.21. From there onwards, scintillation will drop, as the power coefficient approaches a value of 5. For extreme off-axis positions, there will be slight increases in scintillation at high power coefficient values. At points near on-axis and when the beams have small width sizes, cosh Gaussian beam having a bigger displacement parameter will offer the lowest scintillation. At large width sizes, this advantage will switch to the side of the cos Gaussian beam. In this study, the variation of scintillation with other sources and propagation parameters is examined as well.
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