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Gamers, pool and strategies of information architecture
Full text linkPlay is a human activity which requires the creation of a convention, obeying the rules, and which leads to a result that can be evaluated in the light of established criteria. The rules of games interact with the characteristics of the historical periods in which they arose. The I nformation Age provides tools that facilitate the formalization of perception and representation. The article analyses the impact of this fact on architectural strategies. I t describes the background and nature of information games
The Systematic Design of CO2 Capture Rocesses Applied to the Oxidative Coupling of Methane
Full text linkThe oxidative coupling of methane is the catalytic conversion of methane into ethene. Carbon dioxide is generated as a reaction by-product and must be removed from the gaseous stream. In this paper, the application of a hybrid carbon dioxide removal process including absorption with amines and gas separation membranes is investigated through simulations and cost estimations
Optimization of a curvilinear thread profile in a planetary roller screw
Full text linkThe paper presents an application of the Finite Element Method (FEM) in stress analysis and optimization of thread profiles in cooperation of the roller with the screw in the planetary roller screw mechanism. The problem of the roller and the screw threads cooperation as well as related geometrical parameters were described. The optimization problem was formulated with the aim of obtaining a better effort of threads and lower contact pressure depending on the geometry
Characterization of shear stress distribution on a flat roof with solar collectors
Full text linkIn the search for new renewable energy sources, photovoltaic systems and solar thermal collectors have become more common in buildings. With increased efficiency and demand for energy, solar power has also become exploitable at higher latitudes where snow is a major load on buildings. For flat roofs, one usually expects approximately 80% of the snow to be eroded off the roof surface. Installing solar panels would change this since the flow pattern and wind conditions on the roof are affected by their presence. This study shows the erosion of sand particles from underneath solar panels of various configurations associated with different wind velocities. The pattern of erosion is used to determine the relative friction velocity, u*REL, of the wind on the roof. This value is the friction velocity on the roof relative to the friction velocity on a flat roof without solar panels. The experiments, conducted in a wind tunnel, showthat the area where u*REL is 0 and where it is expected that sand and snow will accumulate in case of an upwind particle source and decrease with increasing distances between roof and solar panel. It is also shown that a larger gap between the solar panel and roof surface creates larger erosion zones, where u*REL > 1 for both wind directions. Since the erosion is closely linked to the air flow under the solar panels, and that higher air velocity increases the erosion, it is likely that a larger solar panel, extending higher into the free air flow would be desirable to avoid snow accumulation on a flat roof with solar panels. If the solar panel has large enough dimensions, the solar panels can be used as a deflector to decrease snow accumulation on flat roofs. With solar panels of the size in the current experiments, a building with a length smaller than the equivalent of x/L = 0.3 would have u*REL > 1 on most of the roof surface and would thus likely have a lower snow load than an equivalent float roof without solar panels
Analysis of integral parameters in a single-phase slotless axial-flux machine used in small wind turbines
Full text linkThe design of a ferrite magnet generator with trapezoidal shaped permanent magnets and coils for a wind turbine is studied. Based on the 3-D finite element analysis (FEA), the electromagnetic performances of the two generator prototypes and a simple design modification for one of the axial-flux generator prototypes are analyzed. The best generator is chosen from a range of designs, where the goal is to increase the voltage generated by the 8/8 pole and a single-phase slotless machine. Experimental results from a small size prototype machine validate the 3-D FEA models presented, and hence give confidence in their use for design
FEMM utilisation in representation of inductance distributions in a salient pole synchronous generator circuital model in no-load state
Full text linkThis paper concerns a circuital model of a 5.5 kVA salient pole synchronous generator with damping bars, with and without the rotor skew. The paper presents an influence of the stator to rotor self and mutual inductance distribution on the induced voltages in the no-load steady state. Inductance distributions used in the circuital model are determined in the FE MM program for linear and nonlinear magnetic circuit. Simulation and experimental verification are presented
An Evaluation of the Changes to the Mechanical Properties of Polymer Biocomposites Resulting from their Long-Term Storage at Low Temperatures
Full text linkThis paper presents an analysis of the properties of biocomposites that were stored for four years in the refrigerator at 6°C and were investigated for detailed information of mechanical properties like tensile strength and bending. The study was based on test results obtained in 2011. Comparison of changes in the structure of composite materials was carried out an analysis of SEM image. Matrix filling materials were made of wood fibres and tuff
Drawing and painting? Definitely! The role of painting and drawing workshops after the first year of studies at the faculty of architecture
Full text linkThere is a long tradition of painting and drawing workshops offered after the first year of studies at the Faculty of Architecture of the Cracow University of Technology. In view of the limited number of teaching hours devoted to painting and drawing throughout the academic year, workshops constitute an indispensable element of artistic education and prove useful in the course of subsequent professional activities. Classes are held outdoors, in various spots all over Kraków, and last for five days. For the past several years, plein-air workshops have been organized in Chełmno for groups of ten. During the plein-air workshop, which is not comparable to class-room painting sessions, students work in constant close contact with architects and visual artists, whose professional tips and advice enable them to expand their experience in drawing and painting
The influence of cryogenic temperatures on the characteristics of a brushless motor
Full text linkThis article presents the results of a study on the magnetic properties of soft magnetic powder composites at room temperature and at liquid nitrogen temperature. The properties of a magnetoelectric motor with the power of 0.75 kW at room temperature and cryogenic temperatures are also presented in this article. The study of magnetic properties showed that magnetization curves at 20°C and -195.8°C temperatures are almost the same. Iron loss in the composite at liquid nitrogen temperature increased significantly in comparison to loss at room temperature. The study of the magnetoelectric motor showed that the back electromotive force at liquid nitrogen temperature decreases insignificantly in comparison to the back electromotive force at room temperature. Electromagnetic torque at liquid nitrogen temperature increases in comparison to room temperature
Heat transfer of ice slurry flowing in rectangular and slit chanels
Full text linkThis paper presents the results of experimental investigations into heat transfer between the wall and ice slurry during its flow through channels of rectangular and slit cross-sections. Ice slurry flow is treated as a generalized flow of a non-Newtonian fluid. The influence of solid particles, the flow character, as well as the cross-section of the channel on the heat transfer coefficient are discussed. As the final result, the dimensionless dependences for the calculation of the Nusselt number value in the range of laminar and turbulent flows are presented