Mechanized welding of chosen weld types of iron aluminides by using method 141

katedra: KSP; přílohy: 1 CD ROM; rozsah: 70This thesis is focussed in mechanical welding of chosen weld types of iron aluminides by using 141 method. First of all it was necessary to make the acquaintance of welding 141 by ČSN EN ISO 4063 standard and with characteristics of iron aluminides. For optional realisation of the thesis goal the new experimental center was created. The whole process of welding was recorded by monitoring system WeldMonitor. We investigate if change of parameters take some effect on welding pool geometry, structure or weld quality. The results will attend on improving possible simulation of welding process by using SYSWELD program.Tato diplomová práce se zabývá mechanizovaným svařováním vybraných typů svarů aluminidu železa metodou 141. Nejprve bylo nutné seznámit se s metodou svařování 141 podle ČSN EN ISO 4063 a s technologickými vlastnostmi aluminidů železa. Pro možnou realizaci cílů diplomové práce bylo zhotoveno zcela nové experimentální pracoviště. Celý proces svařování byl zaznamenán pomocí monitorovacího systému WeldMonitor. Zjišťoval se vliv parametrů na geometrii svarové lázně, strukturu a vlastnosti svaru. Výsledky poslouží k zdokonalení možné simulace svařovacího procesu v programu SYSWELD

Comparison of GPS slant wet delays acquired by different techniques

This paper discusses the quality of slant wet delays (SWD) computed from GPS measurements. The SWDs are generally used as input data for GPS tomography, which allows the three-dimensional reconstruction of water vapour distribution in the atmosphere. The research presented is based on a comparison of slant wet delays acquired by different strategies based on double-differenced Global Positioning System (GPS) data. The GPS-derived SWDs were compared with those directly measured by a water vapour radiometer (WVR). The best results from the applied GPS strategies were achieved by a simple mapping of GPS-derived zenith total delays into SWD without adding horizontal gradients or post-fit residuals.Web of Science9443342

Estimating the impact of Global Navigation Satellite System horizontal delay gradients in variational data assimilation

We developed operators to assimilate Global Navigation Satellite System (GNSS) Zenith Total Delays (ZTDs) and horizontal delay gradients into a numerical weather model. In this study we experiment with refractivity fields derived from the Global Forecast System (GFS) available with a horizontal resolution of 0.5 degrees. We begin our investigations with simulated observations. In essence, we extract the tropospheric parameters from the GFS analysis, add noise to mimic observation errors and assimilate the simulated observations into the GFS 24h forecast valid at the same time. We consider three scenarios: (1) the assimilation of ZTDs (2) the assimilation of horizontal delay gradients and (3) the assimilation of both ZTDs and horizontal delay gradients. The impact is measured by utilizing the refractivity fields. We find that the assimilation of the horizontal delay gradients in addition to the ZTDs improves the refractivity field around 800 hPa. When we consider a single station there is a clear improvement when horizontal delay gradients are assimilated in addition to the ZTDs because the horizontal delay gradients contain information that is not contained in the ZTDs. On the other hand, when we consider a dense station network there is not a significant improvement when horizontal delay gradients are assimilated in addition to the ZTDs because the horizontal delay gradients do not contain information that is not already contained in the ZTDs. Finally, we replace simulated by real observations, that is, tropospheric parameters from a Precise Point Positioning solution provided with the G-Nut/Tefnut software, in order to show that the GFS 24h forecast is indeed improved when GNSS horizontal delay gradients are assimilated in addition to GNSS ZTDs; for the considered station (Potsdam, Germany) and period (June and July, 2017) we find an improvement in the retrieved refractivity of up to 4%.Web of Science111art. no. 4

Benchmark campaign and case study episode in central Europe for development and assessment of advanced GNSS tropospheric models and products

Initial objectives and design of the Benchmark campaign organized within the European COST Action ES1206 (2013–2017) are described in the paper. This campaign has aimed to support the development and validation of advanced Global Navigation Satellite System (GNSS) tropospheric products, in particular high-resolution and ultra-fast zenith total delays (ZTDs) and tropospheric gradients derived from a dense permanent network. A complex data set was collected for the 8-week period when several extreme heavy precipitation episodes occurred in central Europe which caused severe river floods in this area. An initial processing of data sets from GNSS products and numerical weather models (NWMs) provided independently estimated reference parameters – zenith tropospheric delays and tropospheric horizontal gradients. Their provision gave an overview about the product similarities and complementarities, and thus a potential for improvements of a synergy in their optimal exploitations in future. Reference GNSS and NWM results were intercompared and visually analysed using animated maps. ZTDs from two reference GNSS solutions compared to global ERA-Interim reanalysis resulted in accuracy at the 10 mm level in terms of the root mean square (rms) with a negligible overall bias, comparisons to Global Forecast System (GFS) forecasts showed accuracy at the 12 mm level with the overall bias of −5 mm and, finally, comparisons to mesoscale ALADIN-CZ forecast resulted in accuracy at the 8 mm level with a negligible total bias. The comparison of horizontal tropospheric gradients from GNSS and NWM data demonstrated a very good agreement among independent solutions with negligible biases and an accuracy of about 0.5 mm. Visual comparisons of maps of zenith wet delays and tropospheric horizontal gradients showed very promising results for future exploitations of advanced GNSS tropospheric products in meteorological applications, such as severe weather event monitoring and weather nowcasting. The GNSS products revealed a capability of providing more detailed structures in atmosphere than the state-of-the-art numerical weather models are able to capture. In an initial study on the contribution of hydrometeors (e.g. cloud water, ice or snow) to GNSS signal delays during severe weather, the effect reached up to 17 mm, and it was suggested that hydrometeors should be carefully accounted for within the functional model. The reference products will be further exploited in various specific studies using the Benchmark data set. It is thus going to play a key role in these highly interdisciplinary developments towards better mutual benefits from advanced GNSS and meteorological products.Web of Science973008298

Inter-technique validation of tropospheric slant total delays

An extensive validation of line-of-sight tropospheric slant total delays (STD) from Global Navigation Satellite Systems (GNSS), ray tracing in numerical weather prediction model (NWM) fields and microwave water vapour radiometer (WVR) is presented. Ten GNSS reference stations, including collocated sites, and almost 2 months of data from 2013, including severe weather events were used for comparison. Seven institutions delivered their STDs based on GNSS observations processed using 5 software programs and 11 strategies enabling to compare rather different solutions and to assess the impact of several aspects of the processing strategy. STDs from NWM ray tracing came from three institutions using three different NWMs and ray-tracing software. Inter-techniques evaluations demonstrated a good mutual agreement of various GNSS STD solutions compared to NWM and WVR STDs. The mean bias among GNSS solutions not considering post-fit residuals in STDs was -0.6 mm for STDs scaled in the zenith direction and the mean standard deviation was 3.7 mm. Standard deviations of comparisons between GNSS and NWM ray-tracing solutions were typically 10 mm +/- 2 mm (scaled in the zenith direction), depending on the NWM model and the GNSS station. Comparing GNSS versus WVR STDs reached standard deviations of 12 mm +/- 2 mm also scaled in the zenith direction. Impacts of raw GNSS post-fit residuals and cleaned residuals on optimal reconstructing of GNSS STDs were evaluated at intertechnique comparison and for GNSS at collocated sites. The use of raw post-fit residuals is not generally recommended as they might contain strong systematic effects, as demonstrated in the case of station LDB0. Simplified STDs reconstructed only from estimated GNSS tropospheric parameters, i.e. without applying post-fit residuals, performed the best in all the comparisons; however, it obviously missed part of tropospheric signals due to non-linear temporal and spatial variations in the troposphere. Although the post-fit residuals cleaned of visible systematic errors generally showed a slightly worse performance, they contained significant tropospheric signal on top of the simplified model. They are thus recommended for the reconstruction of STDs, particularly during high variability in the troposphere. Cleaned residuals also showed a stable performance during ordinary days while containing promising information about the troposphere at low-elevation angles.Web of Science1062208218

Sensitivity of GNSS tropospheric gradients to processing options

An analysis of processing settings impacts on estimated tropospheric gradients is presented. The study is based on the benchmark data set collected within the COST GNSS4SWEC action with observations from 430 Global Navigation Satellite Systems (GNSS) reference stations in central Europe for May and June 2013. Tropospheric gradients were estimated in eight different variants of GNSS data processing using precise point positioning (PPP) with the G-Nut/Tefnut software. The impacts of the gradient mapping function, elevation cut-off angle, GNSS constellation, observation elevation-dependent weighting and real-time versus post-processing mode were assessed by comparing the variants by each to other and by evaluating them with respect to tropospheric gradients derived from two numerical weather models (NWMs). Tropospheric gradients estimated in post-processing GNSS solutions using final products were in good agreement with NWM outputs. The quality of high-resolution gradients estimated in (near-)real-time PPP analysis still remains a challenging task due to the quality of the real-time orbit and clock corrections. Comparisons of GNSS and NWM gradients suggest the 3 degrees elevation angle cut-off and GPS+GLONASS constellation for obtaining optimal gradient estimates provided precise models for antenna-phase centre offsets and variations, and tropospheric mapping functions are applied for low-elevation observations. Finally, systematic errors can affect the gradient components solely due to the use of different gradient mapping functions, and still depending on observation elevation-dependent weighting. A latitudinal tilting of the troposphere in a global scale causes a systematic difference of up to 0.3 mm in the north-gradient component, while large local gradients, usually pointing in a direction of increasing humidity, can cause differences of up to 1.0 mm (or even more in extreme cases) in any component depending on the actual direction of the gradient. Although the Bar-Sever gradient mapping function provided slightly better results in some aspects, it is not possible to give any strong recommendation on the gradient mapping function selection.Web of Science37344642

Comparison of satellite orbit ephemerides for use in GPS meteorology

This paper discusses GPS (Global Position System) meteorology. The research presented is based on a comparison of values of precipitable water vapour PWV, based on GPS measurements using final and predicted ephemerides of satellite orbits. We analysed recent year’s improvement in predicting ephemerides. We compared the data outputs from a radiosonde using GPS receiver measurements directly from the meteorological station from which the radiosondes were launched. The results indicate a high quality of the predicted ephemerides. This finding makes predicted ephemerides highly usable for near real-time estimations of PWV. To use PWV in meteorological forecast applications, this high speed of PWV values supply is necessary

Phenomenon of Gypsie's prostitution at central and eastern Slovakia

Smyslem této bakalářské práce je, jak název napovídá, především zmapování a popsání vzrůstajícího fenoménu romské prostituce ve zmíněných lokalitách. Nekladu si však ambice předložit vyčerpávající demografické statistiky, nýbrž se budu snažit vhlédnout z antropologické perspektivy pod pokličku tohoto dynamického jevu a poukázat na etnická specifika, která zde prostituci romskou odlišují od prostituce jako takové (běžné, bez etnického vyhranění) a to zejména v motivaci aktérů. Mou základní výzkumnou hypotézou je tvrzení, že tato romská "etnoprostituce" se může odehrávat de fakto pouze v urbánním prostředí, protože narozdíl od romské osady to tamní sociální sítě umožňují.Sense of this bachelor paper is, how we can see in topic, mostly in surveying and describing of increasing phenomenon of gypsie´s prostitution in mentioned localities. I don´t lay any ambitions to provide exhausting demographical statistics, but I will try to look inside in anthropological view underhand of this dynamical appearance and refer on ethnic specifics, which contradistinguishes gypsie´s prostitution from "common" prostitution (it means prostitution without ethnical aspects in my work) mainly in actors-motivation. My basic hypothesis is statement, that gypsie´s (so called) "ethnoprostitution" may take place de facto only at urban environment, because in contrast with typical gypsie´s settlement are there social networks, which enable it.Katedra sociálních vědDokončená práce s úspěšnou obhajobo

Language contact of the East Slovak Romani and the Vlax Romani: Selected ethnohistoric and sociolinguistic aspects

Cílem této práce bylo podrobné zmapování jazykového kontaktu slovenské a olašské romštiny odehrávající se v obci Rožkovany, náležící k Prešovskému samosprávnému kraji a k historické oblasti Šariše, která odedávna ležela na křižovatce různých kulturních vlivů. Střetávaly se tu živly slovenské, polské, maďarské, romské, německé či rusínské a k bohatému (nejen romskému) jazykovému kontaktu tam tedy docházelo dlouhodobě. Snažil jsem proto analyzovat vliv těchto historicko-kulturních procesů na dnešní podobu řeči užívané v romské osadě při zmíněné obci. Kromě diachronního, historiografického zkoumání tohoto kontaktu jsem se zaměřil také na jeho sociolingvistické aspekty, tedy otázky spojené s bilingvismem a multilingvismem, statusem sledovaných romských dialektů a dominantního jazyka a také na dyadické, případně triadické vztahy mezi uživateli těchto jednotlivých jazyků v komunitě, tedy hierarchii přejímání a jazykové jevy provázející zanikání jazyků a některé další aspekty. Práce je založená především na opakovaných terénních výzkumech v obci Rožkovany, sběru nahrávek mluveného jazyka a zúčastněného pozorování. Nezbytností je pak srovnání s dřívějšími prameny týkající se této obce a jejího romského osídlení v pracích Emílie Čajánkové - Horváthové a Ondřeje Podušky.Objective of this paper is detailed exploring and mapping of slovak and vlax romani language contact in the village Rožkovany. This village belongs to Prešov self-governing region and historical area of Šariš, effected from time immemorial by various cultural influences. It is situated on a crossroad of slovakian, polish, hungarian, romani, german or ruthenian cultures and language contact (not only between dialects of romani) was therefore occuring very often for a long time here. I was thus trying to analyze an impact of these historico-cultural processes on a todays form of speech used in romani settlement belonging to mentioned village. Besides diachronic, historiographical research of this contact, I was focusing also on its sociolinguistic aspects like a questions connected to bilingualism and multilingualism, status of monitored romani dialects and dominant language and also on dyadic or even triadic relationships between users of these particular languages inside community, it means hierarchy of acceptance and linguistic phenomena accompanying disappearance of languages and some other aspects. This work is mainly based on repeated fieldworks in Rožkovany, collections of recordings of a spoken language and participate observation. Necessity is also a comprison with earlier sources linked with this village and its romani settlement in papers of Emília Čajánková - Horváthová and Ondřej Poduška.Katedra sociálních vědStudent se vyjádřil k metodologickým výhradám oponent