Leading topic of this article is description of Lorentz forces in the container with cuboid shape. Inside of the container is an electrically conductive melt. This melt is driven by rotating magnetic field. Numerical simulations of these unsteady flows were performed in commercial sofrware Ansys Fluent (version 13). Input data (Lorentz forces in the container with cuboid shape) were also obtained from the computing program NS-FEM3D, which uses DDES method of computing as a turbulent approach. Related velocity field of the melt inside the container was displayed and described as well. and Obsahuje seznam literatury
Two new species of Rhinebothrium (Cestoda, Rhinebothriidea) from potamotrygonid stingrays in the Neotropical region are herein described, which raises the total number of Rhinebothrium species known from Neotropical freshwaters to five. Rhinebothrium corbatai sp. n., and Rhinebothrium mistyae sp. n. were both collected from Potamotrygon motoro (Müller et Henle), captured in four tributaries of the Paraná River in Santa Fé Province, Argentina. The new species can be distinguished from their congeners, and from each other, by a combination of various features, including worm size (length and number of proglottids), number of loculi per bothridium, microthrix pattern, size of the cirrus sac, and the extent of the vas deferens. The discovery of these new species from P. motoro supports the pattern of high host specificity in this cestode genus, and reinforces the notion that some of the previous records of the enigmatic R. paratrygoni may correspond to new species of Rhinebothrium yet to be described.
Hyperspectral imaging as a tool for obtaining information about the world around us is rapidly developing field of modern technology. The desired information in such systems is obtained by processing ofstored spectral information of a measured scene. The main advantage of the hyperspectral systems is the use of a wide spectral range encompassing both the visible and adjacent spectral regions(primarily infrared). The main element in these systemsis a spectrally selective element which provides separation of the individual spectral components. This element can be based on number of physical principles, in this paper we will discuss the design and fabrication of a spectral element based on a diffraction grating. The main requirements for this system were: spectral division function for LWIR (7 mm - 14 mm), the highest possible efficiency in this spectral region with respect to the spectral emission of a black body with temperature 350 K, and avoidance of the restrictions given by the production. Design of the grating was done with the use of a scalar theory and the results were compared with RCWAand finite element method. Fabrication of the grating was carried out using single-point diamond turning. The grating was made of germanium. and Hyperspektrální zobrazování, jakožto nástroj pro získávání informací o světě kolem nás, je rychle se rozvíjející oblast moderní techniky. Požadovaná informace se v takových systémech získává zpracováním uložené spektrální informace z měřené scény. Jednou z výhod hyperspektrálního systému je užití širokého spektrální rozsahu obepínajícího jak viditelné, tak i přilehlé spektrální oblasti světla (především infračervenou). Hlavní prvek v těchto systémech je spektrálně selektivní člen zajišťující separaci jednotlivých spektrálních komponent. Tento člen může být založen na různých fyzikálních principech, v rámci tohoto příspěvku diskutujeme návrh a výrobu spektrálního elementu založeného na difrakční mřížce. Hlavní požadavky na tento systém jsou spektrálně selektivní funkce pro LWIR (7 mm - 14 mm), co možná nejvyšší účinnost v dané spektrální oblasti vzhledem k spektrálnímu vyzařování černého tělesa o teplotě 350 K a vyhnutí se omezení daných výrobou. Návrh mřížky vychází ze skalární teorie elektromagnetického pole a výsledek je porovnán s RCWA a metodou konečných prvků. Vlastní výroba mřížky se provedla jednobodovým diamantovým soustružením do germania.
Casing is an imporant part of Vertical Pelton Turbine unit, which acts as a housing for runner and the suppport for Generator. The design of casing requires consideration of hydraulic as well as mechanical aspects. The size and shape of the casing should be designed to give proper guidance to water flow. Casing should have enough strength to meet the mechanical/structural requirements such as to withstand the dead weight of the generator, forces developed in the manifold/branch pipes, load due to the four jets in different combinations and load due to various actuation mechanisms. After satisfying above aspects, the casing should be checked for vibration behavior by modal analysis. The design of casing for four jet vertical Pelton turbine is carried out considering all above mentioned criterion. Ansys Mechanical software is used to study the structural behavior of casing and also for weight optimization by reducing the thickness of casing and changing arrangement of ribs. and Obsahuje seznam literatury
The first part of this article introduces formulas for dimension of motor-size in the case in which an electrical machine replaces the combustion engine. There were shortly described various types of electrical drives that can be applied to drive electrical cars: DC machine, brushless DC machine and induction motor. There are derived differential equations both of electric and mechanic part of the system. As a result of simulation that was performed using MATLAB/SIMULINK there are compared two alternative time-responses of acceleration: with an automatic controlled gearbox and with a manual operation. There were simulated motor-current, battery-current, angular speed of the motor and speed of the car during acceleration. and Obsahuje seznam literatury
A control system architecture design for an underwater ROV, primarily Class I - Pure Observation underwater ROV is presented in this paper. A non-linear plant model was designed using SolidWorks 3D modeling tool and is imported to MATLAB as a 3D model. The non-linear modeled plant is linearized using the MATLAB linear analysis toolbox to have a linear approximate model of the system. The authors designed controllers for the linear plant model of underwater ROV. PID controllers are utilized as a controller of the modeled plant. The PID tuning tools by MATLAB are utilized to tune the controller of the plant model of underwater ROV. The researchers test the control design of underwater ROV using MATLAB Simulink by analyzing the response of the system and troubleshoot the control design to achieve the objective parameters for the control design of underwater ROV.
A vital topic regarding the optimum and economical design of rigid boundary open channels such as sewers and drainage systems is determining the movement of sediment particles. In this study, the incipient motion of sediment is estimated using three datasets from literature, including a wide range of hydraulic parameters. Because existing equations do not consider the effect of sediment bed thickness on incipient motion estimation, this parameter is applied in this study along with the multilayer perceptron (MLP), a hybrid method based on decision trees (DT) (MLP-DT), to estimate incipient motion. According to a comparison with the observed experimental outcome, the proposed method performs well (MARE = 0.048, RMSE = 0.134, SI = 0.06, BIAS = -0.036). The performance of MLP and MLP-DT is compared with that of existing regression-based equations, and significantly higher performance over existing models is observed. Finally, an explicit expression for practical engineering is also provided.