Statistical investigation of gravity wave propagation in the Czech Republic and above

2020 ◽  
Author(s):  
Jaroslav Chum ◽  
Katerina Podolska ◽  
Jan Rusz ◽  
Jiri Base
Keyword(s):  
Czech Republic ◽  
Large Scale ◽  
Statistical Investigation ◽  
Three Dimensions ◽  
Diurnal Changes ◽  
Radio Waves ◽  
The Czech Republic ◽  
Radio Signals ◽  
System Operating ◽  
Propagation Velocities

<p>Propagation of gravity waves (GWs) is studied in the troposphere and thermosphere/ionosphere. The investigation of GW propagation in the troposphere is based on measurements by large scale array of absolute microbarometers with high resolution that is located in the westernmost part of the Czech Republic. On the other hand, the propagation of GWs in the thermosphere/ionosphere is observed remotely, using multi-frequency and multi-point continuous HF Doppler sounding system operating in the western part of the Czech Republic. The reflection heights of sounding radio waves of different frequencies are determined from ionospheric sounder, located in Pruhonice in the vicinity of Prague. Propagation velocities and directions are in both cases calculated from time/phase delays between signals recorded at different locations. The investigation of propagation of GWs in the ionosphere is performed in three dimensions as the observation points (reflection points of radio signals) are separated both horizontally and vertically. It is shown that GWs in the ionosphere usually propagate with wave vectors directed obliquely downward, which means upward propagation of energy. In addition, seasonal and diurnal changes of propagation directions were found. Typical propagation velocities of GWs observed at ionospheric heights are much higher (~100 to 200 m/s) than those observed on the ground (several tens of m/s).        </p>

scholarly journals Statistical investigation of gravity wave characteristics in the ionosphere

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Jaroslav Chum ◽  
Kateřina Podolská ◽  
Jan Rusz ◽  
Jiří Baše ◽  
Nikolai Tedoradze
Keyword(s):  
Gravity Waves ◽  
Rest Frame ◽  
Statistical Investigation ◽  
Three Dimensions ◽  
Diurnal Changes ◽  
Radio Waves ◽  
Neutral Winds ◽  
Wave Characteristics ◽  
The Earth ◽  
Radio Signals

AbstractPropagation of medium-scale gravity waves (GWs) in the thermosphere/ionosphere is observed remotely, using multi-frequency and multi-point continuous Doppler sounding system located in the western part of Czechia. Reflection heights of the sounding radio waves are determined from a nearby ionosonde. Phase velocity vectors of GWs are calculated from time/phase delays between signals corresponding to different transmitter–receiver pairs that reflect in the ionosphere at different locations. As various frequencies reflect at different heights, reflection points of radio signals are separated both horizontally and vertically, and the investigation of GW propagation in the ionosphere is performed in three dimensions. Results obtained for two 1-year periods representing the solar maximum (July 2014–June 2015) and current solar minimum (September 2018–August 2019) are presented. It is shown that GWs in the ionosphere usually propagated with wave vectors directed obliquely downward. A statistical distribution of wave vector elevation angles is presented. A model of neutral winds is used to estimate the wave characteristics in the wind-rest frame. It is found that the distribution of elevation angles is narrower in the wind-rest frame than in the Earth frame. Seasonal and diurnal changes of propagation directions and attenuations of GWs are discussed. The wind-rest frame wavelengths of the analyzed GWs were usually from ~ 80 to 300 km, and the propagation velocities were mostly between ~ 100 and ~ 220 m/s.

scholarly journals The development of regional differentiation of office construction in the Czech Republic: 1990–2010

2015 ◽  
Vol 23 (1) ◽  
pp. 21-33
Author(s):  
Pavel Domalewski ◽  
Jan Baxa
Keyword(s):  
Spatial Distribution ◽  
Czech Republic ◽  
Questionnaire Survey ◽  
Large Scale ◽  
Capital City ◽  
Office Building ◽  
Regional Differentiation ◽  
Key Factors ◽  
The Czech Republic ◽  
Dominant Position

Abstract The factors that were crucial for the construction of administrative buildings in the regional capitals of the Czech Republic are subject to examination in this article. One primary question is whether the development of office construction reflects the qualitative importance of the cities, or whether there are some other regularities in the spatial distribution of construction. To identify the key factors, controlled interviews with experts professionally involved in the construction of administrative buildings were carried out, and these data were then extended as part of a large-scale questionnaire survey with other experts on the issue. The results have confirmed the dominant position of the capital city of Prague in terms of its qualitative importance, as the remaining regional capitals have less than one-tenth of the volume of modern office building areas. The greatest differences in the construction of administrative buildings have been noted in Brno and Ostrava, despite the fact that they exhibit similar characteristics when considered in the light of respondent-determined factors.

Lean home services in Czech Republic

2019 ◽  
Vol 10 (3) ◽  
pp. 784-802
Author(s):  
Felipe Martinez
Keyword(s):  
Czech Republic ◽  
Large Scale ◽  
Assessment Tool ◽  
Future Research ◽  
Lean Management ◽  
The Czech Republic ◽  
Content Type ◽  
Services Sector ◽  
Main Challenge ◽  
Size Limits

Purpose The purpose of this paper is to present the findings of an empirical research on the leanness of the home services sector in the Czech Republic. The automotive sector provides reference to argue the numerical outcomes. Design/methodology/approach The research uses a specifically designed assessment tool (Lean Index – LI) to determine the sector’s leanness level. Referring to the results from both sectors, the paper draws conclusions about the current leanness level of home services providers. Findings The proposed LI indicates a value of 69.50 per cent for home services providers, whereas the LI for the automotive industry suppliers is 82.88 per cent. This suggests that there are large opportunities for the implementation of lean management in the home services sector. However, the main challenge is to introduce a continuous improvement approach to these companies. Research limitations/implications The sample size limits the generalisation of the research results. However, this paper represents the first empirical attempt to implement a large-scale survey. The results are limited to the Czech Republic. However, parties from other countries have indicated interest to replicate the research. Practical implications This research provides first empirical findings on the possibilities of implementing lean in the home services sector. Future research projects in other sectors will have the opportunity to make use of the LI assessment tool. Originality/value The paper presents the first approach of lean management into the home services sector. It provides valuable information to specialised institutions in the sector about the possibilities of lean management in the sector. It also provides an overview of the sector for practitioners and academics willing to pioneer lean in the sector.

scholarly journals Analysis of land-law relations development in the Czech Republic after 1989 in the legal and economic kontext

2009 ◽  
Vol 55 (No. 5) ◽  
pp. 250-256
Author(s):  
J. Bartůšková ◽  
J. Homolka
Keyword(s):  
Czech Republic ◽  
Large Scale ◽  
Agricultural Land ◽  
Direct Consequence ◽  
Scale Production ◽  
The European Union ◽  
Land Law ◽  
The Czech Republic ◽  
Large Scale Production ◽  
Czech Land

Changes in the land law, which occurred after 1948, still influence the whle Czech countryside to this day. Typical features of Czech agriculture, i.e. the fragmentation of ownership of the agricultural land fund and the high share of leased agricultural land, which is a direct consequence of the socialistic large-scale production, continue even despite extensive legal changes after 1989. The changes in the Czech land law after 1989 brought about not only the legal guarantees for owners but also new problems, which are still necessary to solve. An important tool of the solution of the present Czech agriculture problems is represented by land adjustments. The membership of the Czech Republic in the European Union on one hand led to the simplification of land acquisition for some foreigners, however; on the other hand it has not influenced in principle the structure of landowners. Still in 2008, the questions of the atonement of property injustices are finished yet regarding the churches concerning agricultural and forest land. A new civil code, currently in process, which can influence some legal relations to the land, has not been put forward to the Parliament yet.

Large Scale Fracture Mechanics Testing

2008 ◽  
Author(s):  
Milan Brumovsky
Keyword(s):  
Czech Republic ◽  
Fracture Mechanics ◽  
Pressure Vessel ◽  
Large Scale ◽  
The Other ◽  
The Czech Republic ◽  
Short Overview ◽  
Scale Models ◽  
Leak Before Break ◽  
Reactor Pressure

This paper gives a short overview of experimental programs using large scale models/experiments realized in the Czech Republic with the aim to support the reactor pressure components of WWER type reactors. One part of the program was concentrated on reactor pressure vessel components only. It contained flat specimens with defects on one side and models with stress concentrators (nozzles, bolting joints) on the other side. Second part of the program was a part of the LBB (Leak-before-break) project applied to all WWER safety related pipings. Large scale models with defects, located in heterogenous (safe-end) as well as homogenous welds are described.

scholarly journals Shopping centre - a new phenomenon and developing consumer behaviour in the transformation period

Geografie ◽  
2003 ◽  
Vol 108 (4) ◽  
pp. 277-288 ◽  
Author(s):  
Jana Spilková
Keyword(s):  
Czech Republic ◽  
Large Scale ◽  
Consumer Behaviour ◽  
Social Geography ◽  
Social Processes ◽  
Spatial Structures ◽  
The Czech Republic ◽  
Shopping Centre ◽  
Shopping Behaviour ◽  
Shopping Centres

This article deals with the question of large-scale retail concepts and in particular with the phenomenon of shopping centres. First, the issues of location and management of large shopping centres are discussed and basic problematical aspects of shopping centres are indicated. The situation of shopping centres and hypermarkets and their development in the Czech Republic are also shortly described. The second part of the article characterises emerging consumer behaviour and some ways of research into this question within this specific field of geography. Foreign experience and research methods concerning consumer behaviour are used in the study of the situation in the Czech Republic. A new model of developing shopping behaviour of customers in transforming economies is postulated. The model follows the basic perspective of social geography, i.e. the interaction between social processes and spatial structures.

scholarly journals Vývoj komunikačního prostředí simulátoru na podporu řešení krizových situací

2020 ◽  
Vol 19 (2) ◽  
pp. 60-67
Author(s):  
Jiří Barta ◽  
◽  
Jiří Kalenda
Keyword(s):  
Czech Republic ◽  
Crisis Management ◽  
Crisis Communication ◽  
Large Scale ◽  
Crisis Preparedness ◽  
Real Situation ◽  
The Czech Republic ◽  
Simulation Tools ◽  
Form Part ◽  
Considerable Impact

Exercises of the crisis management authorities, which test and verify both plans and capabilities, form part of the crisis preparedness. This article deals with the preparation and implementation of the exercise of crisis management authorities in the Czech Republic. The first part of the article deals with the preparation and putting into practice of crisis preparedness training using software and simulation tools and selected modules, tested at the gas supplies breakdown of large scale. Next part of the article focuses on the training of the crisis management bodies, describing all preparation and implementation phases. The results of the exercise were applied in an evaluation, which detected problems in the field of crisis communication. The exercises tested a simulator, which is being developed. This simulator allowed to record communication and thereby to create conditions similar to the real situation. Simulation has a considerable impact on preparedness due to the possibility to test and verify plans and capabilities of included bodies, identify deficiencies and create an environment for improvements.

Large-Scale Tests Performed in Support of LBB Projects Applied to WWER Type NPPs in the Czech Republic in Years 1992–1994

2009 ◽  
Author(s):  
Dana Lauerova ◽  
Jiri Palyza ◽  
Jiri Zdarek
Keyword(s):  
Czech Republic ◽  
Large Scale ◽  
Bending Moment ◽  
Limit Load ◽  
Computational Results ◽  
The Czech Republic ◽  
Normal Operating ◽  
Two Stages ◽  
Large Scale Tests ◽  
Stable Tearing

In the paper, an overview of large-scale experiments performed on components of WWER primary circuits within several LBB projects conducted in the Czech Republic in years 1992 – 1994 is presented. The tested components were replicas of the real ones; they contained a through-wall crack and were loaded by pressure and bending moment in two stages, as appropriate according to the LBB methodology. All tested components exhibited stable behaviour under normal operating loading superposed with safe shutdown earthquake loading (NOC + SSE) applied during 1st stage of experiment. During 2nd stage of experiment, under loading by bending moment only, the models usually exhibited stable tearing of the crack, in some cases limit load (maximum force at loading controlled by displacement) was reached. In the paper, the experiments are briefly described, with presenting the main experimental and (in some cases) FE computational results.

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