Experimental studies of a two-coherent cross-section blade of wind rotor with vertical axis - motion and a propelling moment of wind turbine

This paper presents experimental studies in a wind tunnel of a two – coherent cross – section blade of wind rotor with vertical axis, mechanism of locating the direction of the wind and planetary rotation of blades. A structure of the blade and results of measurements of aerodynamic forces and aerodynamic torque were shown. Based on received results under some assumptions the propelling moment and unit power were obtained. The results are presented in figures

METHODS OF INTRODUCING ALLOYING ELEMENTS INTO LIQUID MAGNESIUM

In recent years, magnesium alloys have gained widespread popularity as construction materials. This is due to their low density, high strength properties, and advances in their production technology. Properties of magnesium alloys depend primarily on the type, quantity, and quality of elements present in their composition. It is therefore necessary to carry out research on the further optimisation of the production technology of these alloys.This article presents the results of studies carried out in order to determine the type, form, and parameters of the process of introducing selected alloying elements to magnesium in a manner which enables the manufacture of alloys with predetermined chemical composition. As partof the work, elements such as Al, Zn, Mn, Zr, Si, Cu, Ca, as well as rare earth elements (RE) were introduced into the liquid magnesium. The alloying elements were introduced into the melt at different temperatures in either a metallic form or as master alloys. While conducting studies, respective solubility graphs were plotted for the alloying elements showing the time taken for each element to dissolve to the required form at a specific temperature and concentration. The studies resulted in the development of several techniques of introducing selected alloying elements, which enabled the manufacture of various types of alloys

Affective temperament, frontal functions and decision making style in healthy subjects

Wstęp. Celem pracy była ocena cech temperamentu afektywnego i funkcji czołowych u 30 osób zdrowych - pilotów wojskowych, których praca wiąże się z podejmowaniem ryzykownych decyzji. Materiał i metody. Do oceny temperamentu afektywnego zastosowano kwestionariusz Temperament Evaluation of the Memphis, Pisa, Paris, and San Diego Autoquestionnaire (TEMPS-A), Trial Making Task (TMT) i test Stroopa do oceny funkcji grzbietowo-bocznych oraz test Iowa Gambling Task (IGT) do oceny funkcji brzusznoprzyśrodkowych części kory przedczołowej mózgu. Wyniki. W badanej grupie najbardziej nasilone były cechy temperamentu hipertymicznego i depresyjnego. Temperament hipertymiczny wiązał się z ryzykownym stylem podejmowania decyzji w teście IGT, podczas gdy temperament depresyjny korelował z zachowawczym stylem w początkowej fazie procesu decyzyjnego i ryzykownym w końcowej fazie podejmowania decyzji. Wyniki testów TMT i Stroopa nie korelowały z wykonaniem IGT i wynikami skali TEMPS-A. Wnioski. Uzyskane wyniki wskazują na związek temperamentu afektywnego z predyspozycją do podejmowania zadań ryzykownych w pracy i stylem decyzyjnym u osób zdrowych, zaś rola funkcji poznawczych związanych z aktywnością kory przedczołowej grzbietowo-bocznej i brzuszno-przyśrodkowej jest w tych procesach odmienna. Psychiatria 2010; 7, 2: 47-52Introduction. The aim of this work was to assess affective temperament and frontal function in 30 healthy subjects - military pilots, which job is associated with risk decision making. Material and metods. For affective temperament assessment the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Autoquestionnaire (TEMPS-A) were used, Trail Making Test (TMT) and Stroop test for evaluation of dorsolateral prefrontal cortex functions and Iowa Gambling Task (IGT) for ventro-medial prefrontal functions assessment. Results. In investigated group more prevalence was hyperthymic and depressive temperament. Hyperthymic temperament was connected with high risk style of decision making in IGT, while depressive temperament with safe style in first phase of decision making process and high risk style in the terminal phase of decision making. The results of TMT and Stroop test didn’t correlated with IGT performance and also with the results of TEMPS-A scale. Conclusions. The results obtained indicate an association of affective temperament with predisposition to take up risk tasks in the work and style of decision making in healthy persons, however the role of cognitive functions connected with activity of dorsolateral and ventro-medial prefrontal cortex are in these processes different. Psychiatry 2010; 7, 2: 47-5

Numerical and Experimental Determination of the Wind Speed Value Causing Catastrophe of the Scissor Lift

The current work is devoted to the numerical determination of the wind speed value, which can cause the overturning of the mobile elevating work platform of the scissor lift type. In the first step of the analysis, the scaled model of the real vehicle is prepared. In the second step, the model is used in the aerodynamic tunnel to determine the aerodynamic force values and moment, which act on the vehicle. The three different configurations of the work platform are considered, namely: (a) The work platform raised to the maximum height with an additional bridge extended, (b) the work platform raised to the maximum height, and (c) the work platform half raised. In each position, the direction of the wind is changed from the range from 0° to 180° with an increment equal to 15°. In the next step of the analysis, the CFD simulations are carried out. The ANSYS Fluent R22 software is used. As a model of turbulent airflow, the standard k-ε with standard wall function is adopted. The obtained experimental results are used to verify the numerical model. A very good agreement between the results of the experiment and the results of numerical simulations is obtained. As the main result of the numerical study, the values of the tipping moment and corresponding wind speed that cause the overturning of the analyzed real scissor lift are determined. It occurred that the lowest value of the wind speed is obtained for the first variant of the vehicle configuration V1crt = 22.315 m/s for the angle of the wind speed direction β = 30° and the highest one for the third variant V3crt = 34.534 m/s and β = 15°, without any persons on the work platform. The presence of human beings on the work platform is also considered

A vertical-axis rotor as the adjusting system of a horizontal axis wind turbine

The proposed self-adjusting mechanism consists of a carousel rotor with a vertical axis consisting of two kinematically connected flat blades. The torque of this rotor can change the position of the directing unit and additionally the position of the main propeller in order to direct the wind stream or save the main rotor when the wind is too strong. The theory, principles of operation, and the properties of the self-adjusting system were illustrated by formulas and graphs. Based on research conducted in a boundary layer wind tunnel, the values of the aerodynamic coefficients of the flat blades were determined, and then the power and propeller torque of the rotor were found as a function of the angle of wind attack. A computational procedure provides kinematical and force relations as well as the resulting torque diagrams of the rotor. An example of the use and the design structure of a self-adjusting unit in the case of a horizontal axis wind turbine is presented

Numerical and Analytical Estimation of the Wind Speed Causing Overturning of the Fast-Erecting Crane—Part II

The currently presented work is a continuation of the previous one, where the estimation of the forces induced by the wind flow acting on the fast-erecting crane. In that work, the values of the aerodynamic forces were determined experimentally and numerically for the sectional models of the tower and jib. Next, the obtained results were compared with the appropriate standards. Now, the main aim is to determine the critical wind speed causing the overturning of the whole structure. At the very beginning, the numerical analysis of the simplified model of the crane on the real scale is studied. The computations are performed with the use of the ANSYS FLUENT R22. The simulations are performed for three different wind profiles, namely: urban terrain, village terrain, and open terrain. Moreover, the various geometric configurations of the crane in the wind direction are studied. The k-ε model of turbulent flow is exploited. The obtained critical values of the wind speed are confronted with those that are obtained from standards and estimations based on the results obtained from previous investigations performed for sectional models. The influence of the load carried by the crane is also taken into consideration in the overturning of the structure

Comparison of Single and Dual Coherent Blades for a Vertical Axis Carousel Wind Rotor Using CFD and Wind Tunnel Testing

This paper focused on the investigation of the blades for a carousel rotor of a wind turbine with a vertical axis. Cross sections of the single coherent (SC) and the dual coherent (DC) blades were compared in terms of the aerodynamic forces and aerodynamic torque generated during rotor operation for various wind attack angles. The design of the DC blade is novelty proposed by the authors. The main objective of the study was to determine the influence of the blade cross-section on the propelling torque of a wind turbine with three blades, which is an important parameter for rotor starting. First, experimental studies were carried out in a wind tunnel for real-size blade models. A CFD analysis of the airflow around the blades was then conducted. The obtained results were used to evaluate the suitability of applying the studied blade types in the design of the carousel wind rotor. The assessment compared the drag force and the lift force as well as aerodynamic torque as a function of a wind attack angle. It was concluded that the rotor with three DC blades involved mainly the drag force in contrast to the rotor with three SC blades that also involved the lift force to a greater extent. Despite the rotor with DC blades obtained greater values of the drag forces on the blades, the rotor with SC blades obtained a greater starting torque

Optimal Design of Plated/Shell Structures under Flutter Constraints—A Literature Review

Aeroelastic optimization has become an indispensable component in the evaluation of divergence and flutter characteristics for plated/shell structures. The present paper intends to review the fundamental trends and dominant approaches in the optimal design of engineering constructions. A special attention is focused on the formulation of objective functions/functional and the definition of physical (material) variables, particularly in view of composite materials understood in the broader sense as not only multilayered laminates but also as sandwich structures, nanocomposites, functionally graded materials, and materials with piezoelectric actuators/sensors. Moreover, various original aspects of optimization problems of composite structures are demonstrated, discussed, and reviewed in depth

The Wrinkles Characterization in GFRP Composites by Infrared Active Thermography

An experimental study has been carried out to assess the effectiveness of infrared thermography in wrinkle detection in composite GFRP (Glass Fiber Reinforced Plastic) structures by infrared active thermography. Wrinkles in composite GFRP plates with different weave patterns (twill and satin) have been manufactured with the use of the vacuum bagging method. The different localization of defects in laminates has been taken into account. Transmission and reflection measurement techniques of active thermography have been verified and compared. The section of a turbine blade with a vertical axis of rotation containing post-manufacturing wrinkles has been prepared to verify active thermography measurement techniques in the real structure. In the turbine blade section, the influence of a gelcoat surface on the effectiveness of thermography damage detection has also been taken into account. Straightforward thermal parameters applied in structural health monitoring systems allow an effective damage detection method to be built. The transmission IRT setup allows not only for damage detection and localization in composite structures but also for accurate damage identification. The reflection IRT setup is convenient for damage detection systems coupled with nondestructive testing software. In considered cases, the type of fabric weave has negligible influence on the quality of damage detection results