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Nonlinear identification of a spark ignition engine torque based on ANFIS with NARX method

Spark ignition SI engines have a nonlinear dynamic system with inherent uncertainties and unpredictable disturbances. The identification of a nonlinear system is vital in many fields of engineering. In this study, SI engine torque is identified from an input-output measurement. This study aims to propose a dynamic nonlinear model that uses an adaptive neuro-fuzzy inference system and a nonlinear auto-regressive with exogenous input structure to identify the dynamic nonlinear behavior of an SI engine. Considerable good performance is achieved using the adaptive neuro-fuzzy inference system nonlinear auto-regressive with exogenous input method. For model validation, the proposed method is compared with the more conventional identification approach called the Hammerstein method. The results show that the two methods are in excellent agreement. The Hammerstein model was chosen because its identification result of the SI system was studied previously by the author. Validation results prove that the ability of the proposed model can capture the highly nonlinear behavior of the SI system.

Formulation of effects of atropine, pralidoxime and magnesium sulfate on cardiac tissue levels of nitric oxide, malondialdehyde and glutathione in organophosphate poisoning using artificial neural network

Anticholinesterase poisoning is an important health problem in our country, and a complete understanding of its underlying mechanisms is essential for the emergency physician. So, this study focused on two purposes. First one was aimed to investigate the biochemical analysis to determine the tissue levels of malondialdehyde (MDA), glutathione and nitric oxide (NO). Secondly, it was planned to model and formulate the effects of some drugs on cardiac tissues levels of NO, MDA and glutathione in acute organophosphate poisoning in rats by the application of neural network based on experimental results. It has been planned to determine whether artificial neural network (ANN) is appropriate tool to analyze and formulate it. As a result, it has been considered that ANN can be effectively used to model NO, MDA and glutathione level. The performances of ANN formulation versus target experimental values are found to be quite high. It is concluded that, proposed NN models are also presented as simple explicit mathematical functions for further use by researchers.

Free vibrations analysis of fluid conveying nanobeam based on nonlocal elasticity theory

Bu çalışmada, basit-basit ve ankastre-ankastre sınır şartları altında akışkan taşıyan nanokirişin doğrusal titreşimleri incelenmiştir. Eringen’in yerel olmayan elastisite teorisi Euler-Bernoulli kiriş modeline uygulanmıştır. Yerel olmayan elastisite teorisi MEMS ve NEMS yapıların mekaniksel analizinde gelişen popüler bir tekniktir. Hareket denklemlerini ve sınır şartlarını elde etmek için Hamilton prensibi kullanılmıştır. Denklemler boyutsuz formda elde edilmiştir. Elde edilen hareket denklemi ve sınır şartları malzeme ve geometrik yapıdan bağımsız hale getirilmiştir. Akışkan hızının, ortalama sabit bir hız etrafında harmonik olarak değiştiği kabul edilmiştir. Perturbasyon metotlarından biri olan çok zaman ölçekli metot kullanılarak yaklaşık çözümler elde edilmiştir. Perturbasyon serisindeki ilk terim doğrusal problemi oluşturmaktadır. Doğrusal problemin çözümü ile tabii frekanslar ve mod yapıları farklı sınır şartları için hesaplanmıştır. Her iki mesnet durumu için yerel olmayan parametre (γ) ve akışkan hızı (v0) artığında tabii frekanslar azalmaktadır. Sonuçlar grafiklerle sunulmuş ve yorumlanmıştır. In this study, linear vibration analysis of a nanobeam conveying fluid is investigated under simple-simple and clamped-clamped boundary conditions. Eringen’s nonlocal elasticity theory is applied to EulerBernoulli beam model. Nonlocal elasticity theory is a popular growing technique for the mechanical analyses of MEMS and NEMS structures. The Hamilton’s principle is employed to derive the governing equations and boundary conditions. Non-dimensional form of equations is obtained. The obtained equations of motion and boundary conditions are independent from material and geometric structure. It is assumed that fluid velocity is harmonically changed about a constant average speed. Approximate solutions were obtained using the Method of Multiple Scales, a perturbation method. The first term in perturbation series composes linear problem. Natural frequencies and mode shapes are calculated by solving the linear problem for different boundary conditions. For both boundary conditions, the natural frequencies are decreased by increasing the nonlocal parameter (γ) and the fluid velocity (v0). The results are presented and interpreted by graphics.