Archiv článků od 15.11.2015 do 3.4.2017

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Microwave theory in construction practice

3.4.2017 | Ing. Jindřich Sobotka, Ph.D., doc. Ing. Karel Šuhajda, Ph.D., VUT Brno, Fakulta stavební, Ústav pozemního stavitelství, Mgr. Zdeněk Jiroušek, S.P.UNI, s.r.o
This paper discusses the practical use of microwave technology in construction practice. Opinions on the use of EMW devices are not only among the general public quite different. From boundless praise, to the uncritical condemnation. The reason for this situation is the lack of awareness of experts and the public about what is and what is not possible to expect from this technology.The article conclusions which we reached on the basis of experiments conducted at the Faculty of Civil Engineering Brno and subsequently verified measurements in field practice. The aim is to provide basic information about how to use microwave technology. Their benefits but also the risks that this technology brings along.
1 comment, 04.04.2017 15:22

The invention, patent or utility model - who should sort?

8.3.2017 | Ing. Zdeněk Lyčka
The article explains the differences between the invention patents and utility model from the perspective of Czech legislation. Also highlights the confusion individual categories and purposeful fraud by producers and sellers of equipment.
1 comment, 08.03.2017 07:44

Measurement and Evaluation of the Significant Sources of Natural Radioactivity

6.3.2017 | prof. Ing. Leonard Hobst , CSc., VUT v Brně
The natural radioactivity lives mankind throughout its development. The effects of radiation to some extent they can influence the evolutionary history of life on Earth. It is therefore important to determine what values the natural radioactivity would reach different locations of the world.

Crushed Straw Used as a Building Material

20.2.2017 | Ing. Jiří Teslík, Ing. Petr Kurečka, Ing. Naďa Zdražilová, VŠB Technická univerzita Ostrava, Fakulta stavební
Natural building materials are in recent years used still more often in civil engineering. One of these materials is also the straw. By its crushing and cutting into small pieces it is formed so-called crushed straw. The properties of this material, which are important for civil engineering, were not published yet unlike the properties of the straw in bales. In the Czech Republic there exist a many objects built from straw bales. In this paper there are described partial results of research which is implemented on Faculty of Civil Engineering, VSB – Technical University of Ostrava since 2013. The aim of this research it is to set fire resistance, thermal – technical properties and acoustical characteristics of crushed straw. There are described results of fire tests – flammability test and tests of single burning object (SBI). Subsequently there are referred results of thermal conductivity measurements, which were provided for different bulk densities of crushed straw.

Micellar solutions and microemulsions for cleaning the historical materials

16.1.2017 | Ing. Jiří Rathouský, CSc., Centrum pro inovace v oboru nanomaterálů a nanotechnologií, Ústav fyzikální chemie Jaroslava Heyrovského, v.v.i., AV ČR
The removal of unwanted material from the surface of historical artefacts is one of the most important and also the most delicate operations in the restoration of cultural heritage. In the Center for innovations in the field of nanomaterials and nanotechnologies a novel design concept of the cleaning microemulsions was developed based on a combination of the two functions, implemented by two components, namely a micellar solution or microemulsion of nonionic surfactants with the addition of co-surfactants and the specific solvents, which are selected according to the respective substances to be removed. The patented cleaning compositions can very effectively and selectively remove coatings of many substances important for the restoration practice, such as waxes, resins (e.g, Damara), paraffins, oils, water acrylate dispersions, hydrophobization coatings (both monomeric and polymeric) etc. Besides the efficient cleaning, the developed procedures have wider applications, such as in a new method of the hydrophobization of sandstone and limestone materials with a thin hydrophilic surface layer, which has been certified by the Ministry of Culture of the Czech Republic.

Nanolime for the consolidation of porous materials

9.1.2017 | Ing. Jiří Rathouský, CSc., Centrum pro inovace v oboru nanomaterálů a nanotechnologií, Ústav fyzikální chemie Jaroslava Heyrovského, v.v.i., AV ČR
Non-aqueous dispersions of nanoparticles of calcium hydroxide and magnesium are principally suitable means for the consolidation of wall paintings and limestone materials because they are compatible with the material of historical artefacts. They are also suitable for the deacidification of paper and wood. In the Center for innovations in the field of nanomaterials and nanotechnologies procedures were developed which provide nanoparticles of calcium hydroxide and magnesium ranging in size from about 10 nm to about 200 nm. The procedures are relatively experimentally challenging and put them into practice will require further technological research. Thanks to the good stability of the dispersion a sufficiently long shelf life is ensured and premature aggregation on the surface or just below the surface of treated materials is prevented. There are several alternative methods of the consolidation stone, as exemplified by the use of alkoxides of calcium or magnesium. In converting the alkoxide to calcium carbonate, the sole by-product is alcohol, which naturally evaporates from the stone.

Reducing of Noise from Sources of Heat and Propagation of Sound

9.1.2017 | Ing. Miroslav Kučera, Ph.D., ČVUT v Praze, Fakulta strojní, Ústav techniky prostředí, Časopis Větrání vytápění instalace
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.

Nearly Zero-Energy Buildings

9.1.2017 | Ing. Jan Antonín, Ph.D., EnergySim, Ing. Magdalena Purkrtová
For more than a year, a nearly zero-energy standard has applied to certain buildings. In the Czech environment, specific technical parameters for such buildings have been known for three years. And for over six years, the Directive on energy performance of buildings has been in force, imposing the obligation upon EU member states to introduce this standard.

Nevertheless, it seems that for many experts, including those in the field of energy, this term is still quite unclear. Many imagine buildings coated with photovoltaic modules from the ground to the roof, buildings which are better than passive ones or buildings which are self-sufficient, i.e. completely independent of public energy networks. Given the fact that the concept of a nearly zero energy building is very distant from such notions, and because this standard will soon become obligatory for all buildings, including small family houses, let's have a look at what a nearly zero-energy building really is.
6 comments, last 12.01.2017 14:25

The Effect of Local Thermal Bridges on Thermal Performance of Curtain Walling

12.12.2016 | Ing. Roman Jirák, Ph.D., Ing. Petr Jaroš, Ph.D., DECOEN znalecký ústav s.r.o.
U-value calculation of curtain walling is one from more difficult calculation in the civil engineering. In according to trend of increasing glassing surface of building envelope, the curtain walling has big influence on thermal behaver of buildings. This is why it is necessary to calculate the thermal insulation properties with special attention. This article focuses on influence of different local thermal bridges on curtain walling U-value.

New CZ-Classification of Roof Underlay - Tightness Classes

24.10.2016 | Jan Rypl
Since year 2000 up to now a similar classification of roof safety waterproofing layer was valid in Czech Republic and in western countries, while in Slovakia is still valid.

In 2011 so-called working group of ROOF CRAFTSMEN ASSOCIATION CZ (Řemeslná rada Cechu KPT ČR) was established, and new Rules for design and construction of roof (Pravidla pro navrhování a provádění střech) (hereinafter „CZ RULES“) were created after 3 years of hard work. These „CZ RULES“ were approved on 28.3.2014 and officially published on 12.9.2014. By these „CZ RULES“ the roof safety waterproofing layer - „PHI“ (pojistná hydroizolace), was renamed to roof additional waterproofing layer - „DHV“ (doplňková hydroizolační vrstva).

The new „CZ RULES“ were made due to changes in building standards in Czech Republic and newly approved version of Rules for design and construction of roof by „ZVDH“ in Germany. The new „CZ RULES“ don´t fully correspond with the German rules, but are very similar.

Fire Aspects of External Thermal Insulation Composite Systems according to the new Standard ČSN 73 0810:2016

1.8.2016 | Ing. arch. Petr Hejtmánek, Ing. Marek Pokorný, Ph.D., Katedra konstrukcí pozemních staveb, Fakulta stavební ČVUT v Praze
External Thermal Insulation Composite System (ETICS) still plays an important role in increasing the energy efficiency of buildings – the bigger is the demand, the thicker is just the insulation layer. In August 2016, a new version of basic fire safety Czech standard ČSN 73 0810 comes into action. Changes stated in this document are related, among other, to ETICS and it significantly changes the use of combustible and incombustible thermal insulation on facades. This article intends to point out the essentials of the mentioned problematics.

RPAS data processing and their applicability in construction

18.7.2016 | prof. Dr. Ing. Karel Pavelka, Fakulta stavební ČVUT, katedra mapování a kartografie
Presented text discusses the use of RPAS (Remotely Piloted Aerial System) in the building industry and heritage preservation. It provides information of various case studies and shows examples. For the purposes of building industry and technological area monitoring multicopter systems are mainly used. They have more complex control, but they can be successfully navigated in very low heights and low speeds around and above the object. Safe handling and ensuring the area after agreement with the owner or facility manager is crucial for their use.

Floor area in living spaces with slanting ceilings

20.6.2016 | Josef Remeš, Ing. et Ing. Petr Hlavsa, Ing. Radim Kolář, Ph.D., Fakulta stavební VUT v Brně
Floor area in living spaces with slanting ceilings has an ambiguous interpretion in czech national regulations. It has an effect on a building approval process and this article describes how to determine this area in both architecture and civil enginnering.
1 comment, 21.06.2016 11:21

Hempcrete – cement composites using natural fibres

18.4.2016 | Ing. Karel Mikulica, prof. Ing. Rudolf Hela, CSc., Fakulta stavební VUT Brno
The paper describes the use of hemp shiv as a natural organic fillers for building materials, especially concrete designed as heat - insulating filler material around the load-bearing structure of wooden buildings. In construction, yet hemp used in the form of mats made of hemp fiber, with the addition of bonding bicomponent fibers and soda solution as protection against burning and rots. Mats are formed by pneumatic fleece, they are subsequently cooked and subsequently cut to the desired dimensions. Calcium-hemp building material is a revolutionary construction and thermal insulating material with which to build the entire building, it is not necessary bricks or other insulation. The trend is spreading across Europe from France, where the mixture shiv and lime used in the 16th and 17th centuries for the construction of timber-framed houses. Although Europe is worth from hemp concrete for hundreds of buildings in our country with its use only timidly begin. Concrete is a mixture of hemp shiv, slaked lime, cement and water. It is a recyclable material that offers high thermal and sound insulation. The biggest advantage is undoubtedly the speed of construction, namely hemp concrete hardens very quickly.
1 comment, 28.02.2017 11:02

Roof steel construction of the O2 Arena

7.3.2016 | Ing. Vladimír Janata, CSc.
Multipurpose O2 (former Sazka) Arena is remarkable building which was given many awards including European Steel Design Award. The article deals with project, production and completation of the Arena's steel construction with plentiful picture and project documentation.
Chladicí rozvody izolované syntetickým kaučukem, foto autor

Technical insulation - use of technical insulation

1.2.2016 | Ing. Vít Koverdynský, Ph.D., Divize Isover
Saint-Gobain Construction Products CZ a.s.

We calculate insulation thickness in accordance with the criterion of maximum heat loss and monitor unwanted warming or cooling media and maintain the required temperature.

Roof of the ice rink in Varnsdorf

18.1.2016 | Ing. David Mareček
The article deals with Varnsdorf ice rink roof project and construction. The supporting structure made form wood and steel was quite complicated due to slanting swivel joint pillars in B and C axes. Three cranes, one lifting platform and one moving scaffold were needed for the construction.

Aviatica – the gate to the new district of former Waltrovka ground

14.12.2015 | Ing. arch. Petr Kučera, Jakub Cigler architekti
In early September, the administration building Aviatica was inaugurated and officially unveiled, which is the flagship of a large development in the former factory Walter in Prague. Use of abandoned industrial sites, called Brownfields has been the great theme of Planning and Development during the last few years. Vast territories with dilapidated buildings have a negative impact on their environment, in terms of the degradation of the environment, environmental stress, negative social phenomena or reduction of the economic potential of the site. These lucrative localities are connected to existing technical and transport infrastructure. The transformation has a positive impact on the surrounding areas and instead of spatial expansion of cities into the countryside is one of the ways to exploit their intrinsic potential.

Quadrio – Return to the City – One year from the opening of the new polyfunctional building in Prague

7.12.2015 | Ing. arch. Petr Kučera, Jakub Cigler architekti
In October 2015, it was one year from when the new polyfunctional building Quadrio in the center of Prague above the metro station Národní třída was opened. It incorporates not only business and office space, but also residential building, a public passage and exit from the metro station. After almost thirty years a big scar of the historic city was healed. It was caused by the construction of the metro station Národní třída, which was accompanied by the demolition of the original buildings and the replacement with single-storey ground lobbies that suit rather to the suburb than the city center. At the same time a new public urban space was created, a stone plaza, which is in the case of similar projects rather rare exception than the rule.

Preservation of a catacombs of a State castle Lednice. Constructional and technical research is an important step of a preproject preparation

15.11.2015 | Zdeněk Štefek, Pavel Zejda, SAREP a.s.
The basement of a castle greenhouse, so called catacombs, and a terrace with air shafts above them are located to the east by the Palm greenhouse of a state castle Lednice and they are connected with it. Catacombs used to serve as depositaries for storing plants from castle park in a period of winter month. Preservation of greenhouse’s catacombs began in 2004 and was carried out in phases till the end of 2007 when the work was interrupted. In 2012 the investor decided to proceed to finish the second part of a planned reconstruction connected with a reconstruction of basements under the greenhouse terrace. The vital part under the project documentation is also dealing with a rehabilitation of damp masonry including necessary constructional and technical research with respect to dampness and its elimination.
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