Czech Republic
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Novak M.,CVUT v Praze
Vytapeni, Vetrani, Instalace | Year: 2017

With increasing demands for energy savings and better efficiency of appliances, the "brushless directcurrent motors" get to the forefront in some application areas. The aim of this article is to briefly show how they work, how they are constructed, what are their parameters and characteristics, typical applications and methods of their control.

The paper seeks to provide a comprehensive view of counter-flow two-pipe heating system from the design perspective of the temperature parameters and related small or large flow rate through the system. It analyses the work of the thermostatic control valves, zone valves and riser valves in systems with small and large flow rate and on the basis of the analysis it evaluates their advantages and disadvantages. It also deals with hydraulic balancing of heating systems and works with the defined term "sensitivity to changes in flow rate".

An important characteristic of refrigerant is aside of the environmental and safety characteristics also energy efficiency, arising from the thermodynamic properties and determining the energy demands for operating the refrigeration system. In the article, energy efficiency of carbon dioxide is compared with selected refrigerants currently used in the field of refrigeration and air conditioning and advantages of its use and examples of use in the Czech Republic are discussed.

The paper deals with CFD simulation of pressure losses of capillary mats. The emphasis is put on the frictional pressure losses for laminar flow in the capillary tubes and on the dynamic pressure losses in the dividing and merging of the flows, where the regime of the flow is changing. The relations of the local loss coefficient for dividing and merging flows and also of the friction coefficient for unstable laminar flow were obtained using CFD simulations.

The paper presents an example of solving the propagation of noise from an air/water heat pump installed in the basement of an apartment building. Air intake and exhaust are brought out on the façade of the building, where it is calculated the noise situation in the protected exterior of the building. In the interior it is solved the propagation of sound from the plant room to the protected interior space. In conclusion, the results are compared with the data from the report on measurement at the realized work.

Kroftova K.,CVUT v Praze
Advanced Materials Research | Year: 2014

The current approach to the restoration of listed buildings emphasizes the minimization of interference and the maintenance of authenticity and historical value as a whole, alongside detail. This opens a wide field of applications for composite materials and nanomaterials. The use of nanotechnology is currently one of the most reviewed areas of research in various technical disciplines. The extraordinary properties of nanomaterials allow their successful use in the restoration of listed buildings. © (2014) Trans Tech Publications, Switzerland.

The paper is focused on the issue of the pipeline networks dilatation. From the perspective of the designer, it is a very simple and well-documented issue. However, as is shown in the article, if the basic requirements are not met when designing the pipeline networks, the results can be quite fatal.

Cvut V Praze | Date: 2014-05-21

A device for a bodys spherical motion control connected with a frame by means of a spherical joint arranged on a shank connecting the body with the frame and through actuating arms with drives, where the shank is sectional and the spherical joint is arranged between the first part of the shank which is firmly fixed to the frame and the second part of the shank which is firmly fixed to the body, whereas the number of parallel arms with drives is redundant. In order to increase the accuracy of both the self-calibration itself and a follow-up positioning of the body in the work area and to achieve a large range of the bodys rotating, the number of parallel arms with drives is five at minimum and the length of the first part of the shank connected to the frame is longer than the distance of the body edge from the point of connection of the shank to the body.

Cvut V Praze | Date: 2013-02-11

The invention concerns a method for setting a position of manipulating arms on a supporting frame and a supporting frame (1) for positioning the manipulating arms fitted with tools (11) for attaching technological or measuring members, where the particular manipulating arms get unblocked for relocation in their placement and/or in their mutually moveable parts, they are relocated by means of a robot into a new demanded position where they are blocked in their placement and/or in their mutually moveable parts. The supporting frame for placement of the manipulating arms is fitted at least with one sliding guide (3) and/or spherical joint (16) in which the manipulating arm consisting at least of two mutually moveable parts is placed moveably, whereas the manipulating arm is fitted with blocking elements for blocking and unblocking motion in its placement and motion of its mutually moveable parts. The blocking elements are connected to a source (7) of pneumatic or hydraulic or electrical power.

The invention relates to the internal structure of a deformation block especially for exits, bridges, overpasses, driveways and similar structures that are constructed in roadside ditches that serve for draining roads. The invention also relates to a deformation block from which bridges, overpasses, driveways and similar structures for all kinds of roads are built and a deformation system which consists of single deformation blocks. The subject matter of the internal structure of the deformation block consists in the fact that it consists of at least two rows of cells, wherein the cell axes in the direction of the impact force in the individual rows of cells are mutually offset. The deformation block for this purpose consists of at least two rows of cells, wherein the cell axes are in different cell rows are mutually offset, and it is provided with a through hole for water drainage. The deformation system consists of at least two deformation blocks that are arranged in a base shaped piece, a rear edge or a baffle of which are partially deformable so that the internal structure of these deformation blocks is crushed against them.

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