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In this paper, a compact size digitally controlled speed driver for travelling wave ultrasonic motor was designed and implemented. Although the driver system is light in weight, simple, small in size, it is possible to enter speed and direction digitally as well as tracking the real motor speed, voltage and current on an LCD. The implemented system was tested in a laboratory for different speed and load cases and obtained results are presented. [ABSTRACT FROM AUTHOR]

In this paper the uniform diffracted fields from an opaque cylinder cut surface are studied with the theory of the boundary diffraction wave(BDW). For an incoming cylindrical wave, first the vector potential is refound. The new generated vector potential is used in the calculation of the scalar electric/magnetic field, for the observation point. The field expression is taken in Helmholtz-Kirchoff integral form. By applying the Stokes theorem, the field expression can be written as the sum of the diffracted wave field and the geometrical optic field. The obtained diffracted wave field expression results in a non-uniform structure. The non-uniform field expression is converted to uniform structure by using the fresnel function. In this work the diffracted wave field from the edge of an opaque cut cylinder is calculated with the boundary diffraction wave theory for the first time. Total scattered field is calculated as the sum of the diffracted and the geometrical optic wave fields in this work. Finally the uniform and non-uniform diffracted wave fields and the total scattered field are examined numerically. [ABSTRACT FROM AUTHOR]

Depending on the flow conditions, the hydraulic jump may occur in the form of both A-jump and B-jump in a rectangular channel with an abrupt drop and constant width. Also depending on this flow condition, "Wave-type flows" may occur between these two flow types. Because, all of these flow types should occur and remain within the stilling basin. The length, height and width of the stilling basin are an important parameter, that should be known in designing of stilling basins. For sizing of stilling basins, flow geometries are as important as these flow conditions. In the present study; the "Wave-type flow" and its geometric properties are experimentally investigated and the results are compared with the available data. In conjunction with the test results; the simple empirical expressions that predict the geometric properties of the maximum Wave-type flow are developed. These empirical expression with the simplest and comprehensible form predict the results better than available empirical expressions. [ABSTRACT FROM AUTHOR]

In this study, the propagation of harmonic waves in an initially inflated and axially stretched, a fibered tubes filled with viscous fluid is studied. The fluid is assumed to be incompressible and Newtonian. An incompressible, anisotropic and elastic structural model is used for the compliant arterial wall. The tube is subjected to an initial static inner pressure, an axial stretch and residual circumferential stress caused by opening angle. The governing differential equations of the problem are obtained in cylindrical coordinates, utilizing the theory of „„Superposing small deformations on large initial static deformations??. The analytical solutions of the equations of motion for the fluid have been obtained. Due to variability of the coefficients of the resulting equations for the solid body, they are solved by finite-difference method. The dispersion relation is obtained as a function of the axial stretch, opening angle, internal pressure and material parameters. The wave speeds and transmission coefficients are numerically calculated and the results are discussed on graphics. [ABSTRACT FROM AUTHOR]

Extensive researches have been conducted about wave runup on smooth sloped breakwaters all over the world for a long time. Runup behavior on rough rock armored slopes are significantly different even under the same wave conditions. However, investigations on rock armored slopes are very limited. Rock armored slopes such as breakwaters and revetments are high-cost structures that defend the area behind them against severe wave attacks and strong currents. Wave runup is a crucial factor dictating the crest level of these structures. Van der Meer conducted extensive series of physical model tests under random sea states for investigating stability of rock armored slopes at Delft Hydraulics Laboratory, during which runup values are measured simultaneously. After qualitative review of various parameter influences concerning wave runup on impermeable, permeable and homogenous rock structures, Van der Meer and Stam proposed the most widely used formulae for the forecast of dimensionless 2% wave runup elevationas as function of surf similarity parameter by using regression analysis, which is also recommended by the U.S. Army Corps of Engineers, British standards. The regression model consists of two parts, namely linear and power functions.. Hence, it is necessary to consider a transition region which depends on the variable surf similarity parameter. Rock armored slopes are often designed according to the runup level exceeded by 2% of the incident waves, u 2% R /Hs, on the front face of the coastal structure by using Van der Meer and Stam formulae. This parameter is defined as the vertical distance between the still-water level and the elevation exceeded by 2% percent of the runup values in the distribution. This means that, for every 100 waves running up a slope, two waves would have a runup elevation exceeding the level estimated by R From the literature survey, it is seen that the two most important factors influencing runup phenomena on rock armored slopes are structure permeability and surf similarity parameter Since the relationships between wave runup and these parameters are complex, vague and uncertain in nature, it is quite difficult to adequately examine wave runup by conventional regressional approaches. Here, an attempt is made to construct various Takagi-Sugeno (TS, 1985) fuzzy models for predicting the 2% wave runup on rock armored slopes. The key task in developing a satisfactory forecasting model in the TS approach is the selection of appropriate input variables and numerical counts and types of Membership Functions of these variables, which determines the architecture of the model. Subsequently, the premise and consequent parameters are optimized by using ANFIS learning procedure. ANFIS, free of restrictive assumptions, optimizes premise and consequent parameters by gradient descent and least-squares methods, respectively, in order to best learn information about the dynamic system and does not contain any transition regions, as in the Meer and Stam equation depending on surf similarity parameter. In this study, many ANFIS models with different architectures are trained with the same 100 training data of Van der Meer and Stam. The training performance of each model is accomplished within a short time. They are compared with conventional empirical model of Van der Meer and Stam and with one another by using the 161 test data. As a result, the system with two inputs, namely structure permeability and surf similarity parameter, and each of which is assigned three trapezium MFs provides a smaller error compared to the empirical and other constructed ANFIS models and therefore is selected. In the constructed model, structure permeability and surf similarity parameter variables are initially assigned three trapezium MFs with equal base widths. Then each parameter in the membership functions in the premise part of fuzzy IF–THEN rules that changes the shapes of the membership function is set to an appropriate value to match the output data of the training data by using the back propagation algorithm. This leads Structure Permeability and Surf similarity parameter variables to different trapezium shapes. The developed fuzzy model with two inputs namely structure permeability and surf similarity parameter yielded the best result out of all constructed models and is proposed in this study. The presented model is validated by comparison with widely used empirical model of Meer and Stam recommended by the U.S. Army Corps of Engineers, using the experimental data-sets of Van der Meer and Stam. The verification process is obtained through scatter diagrams and two numerical error criterias. It was found that the Fuzzy Logic model produce better accuracy in performance than the Van der Meer and Stam’s empirical model. [ABSTRACT FROM AUTHOR]

Reliability of coastal structure is mainly based on maintaining the specified functions of the structure set during its design for a determined time interval and not reaching to the limit damage condition values due to the loading forces of structural resistance. A reliability based risk model is applied to the revetments located in the region between Piraziz-Sarp of the Black Sea coast highway by sampling the uncertainties of the random design parameters with probability distributions using physical properties of armor layer and significant wave height (Hs) of the study area. It is found that the factors affecting the reliability of the revetments are the armor layer slope (cotθ) and the relative stone density (Δ). Damage probability of the structure in its economical life is also calculated. [ABSTRACT FROM AUTHOR]

First and the most important phase of designing high cost coastal structures is to forecast the significant wave height (Hs). In this study, an alternative approach to the deterministic and stochastic methods found in literature is proposed. Neuro-fuzzy is a method in which advantages of Artificial Neural Networks (ANN) and Fuzzy Logic (FL) are combined. In the Neuro-Fuzzy models developed in this study, daily significant wave height can be estimated using daily average Hs and significant wave period (Ts) data. Hs and Ts data recorded at different time intervals were used in the proposed models. In this study, Hs and Ts measured in Filyos region of the Black Sea was estimated by the Adaptive Network-based Fuzzy Inference System (ANFIS). Predicted results from proposed models were compared with the measured wave data and it is found that high correlation values are obtained. It is thus concluded that the proposed models can efficiently be used to estimate missing wave data. [ABSTRACT FROM AUTHOR]

Pulsed magnetic fields are generally within the range of frequencies 30-300Hz that are also called Extra Low Frequency (ELF) waves. They are relatively very low energy transmission that bear no side effects to the body. It is reported that they promote blood circulation and tissue regeneration. In this work, rectangular coil connected biomedical PEMF device has been developed. The magnetic field formulation and simulations have been carried out and verified with related sources in the literature. Compared to the analytical results, our results have yielded less than 0.5% error in theoretical derivations and less than 13,1% in experimental measurements. The work is being carried out to obtain portable prototypes for clinical experiments as well. [ABSTRACT FROM AUTHOR]

Istanbul is the most important city of Turkey in the view of economical, social and cultural aspects. Because of the active faults in the Sea of Marmara, there is always an expectation of an important earthquake that will be harmful for the city and also for the other big cities that are located around the Sea of Marmara such as Bursa, İzmit, Tekirdağ and Yalova. In addition to the earthquake, a tsunami which occurs in the Sea of Marmara can also be a very destructive hazard for Istanbul and other cities around the Sea of Marmara. There are many tsunamis that happened in the Sea of Marmara in the history. The main reason of these tsunamis is the slumps and the landslides that were triggered by an earthquake. One of the most important reasons of the tsunamis on the earth is the submarine landslides. Movement at the sea bottom stirs the above water mass. This causes tsunami waves and these waves damage the coastal areas seriously. The aim of this study is to find the maximum wave heights of possible tsunamis around Tuzla coasts using different scenarios. A submarine landslide that may be occurred after an earthquake or because of any other reason in the Sea of Marmara at the region near to northeast Marmara coasts is taken as the reason of the tsunami in the simulations that are performed in the study. As the solution method, one hybrid method was developed. The main objective of this method is to combine an analytical solution presenting near-field tsunami amplitudes above the submarine mass failure with a numerical solution indicating the tsunami amplitudes in the coastal regions. An analytical model that is frequently used in the literature was applied to find the amplitudes of tsunami waves at the surface of Sea of Marmara above the submarine landslide region. These tsunami waves will be directly affected from the water depth of the Sea of Marmara. It will be also affected by the shore profile when traveling to the coasts. Because of this reason, a computational fluid dynamics model which is based on finite elements method is used in the regions that are very close to the coasts. The model solves the Navier-Stokes equations. Analytical and numerical models were used together in this study. The analytical model is used from the submarine up to sea surface and the numerical model is used for modeling of the movement of the tsunami waves at the sea surfaces. In the border of two models the outputs of analytical model is used as the inputs of numerical model that means the initial and boundary conditions of numerical model is obtained from the analytical model.… [ABSTRACT FROM AUTHOR]