New type of aerodynamic tilting pad journal bearing was designed and successfully tested in several applications, one of which was power gyroscope support. Bearing design combines advantages of foil bearings, i.e. additional damping achieved by squeezing out gas film and friction of elastic elements on bearing casing surface, with qualities of classical tilting pad bearings, consisting in defined geometry of bearing gap and excellent stability. Theoretical solution of bearing characteristic calculation is shortly described, consisting in numerical solution of gas flow in narrow gap. Some computed data and results of experiments with rotors operated up to 180.000 rpm are presented too. and Obsahuje seznam literatury
The scenario forecasting technique for assessing changes of water balance components of the northern river basins due to possible climate change was developed. Three IPCC global emission scenarios corresponding to different possible scenarios for economic, technological, political and demographic development of the human civilization in the 21st century were chosen for generating climate change projections by an ensemble of 16 General Circulation Models with a high spatial resolution. The projections representing increments of monthly values of meteorological characteristics were used for creating 3-hour meteorological time series up to 2063 for the Northern Dvina River basin, which belongs to the pan-Arctic basin and locates at the north of the European part of Russia. The obtained time series were applied as forcing data to drive the land surface model SWAP to simulate possible changes in the water balance components due to different scenarios of climate change for the Northern Dvina River basin.
This paper describes some results of an experiment aimed at monitoring of contact fatigue during the axial bearings tests. The needful of AE set-up for measuring of signal and Axmat stand for testing is presented here. The measuring of some kind of bearings required the creation of new clamping elements (Segment and Bearing bush) to the existing key point of Axmat stand. The results in this paper show records in the time domain mainly for counts and events. These events are filtered by maximal amplitude for better response on signal changes during the lifetime record. For these evaluated records there are shown the final failures of tested bearings and possible causes of failures beginning. and Obsahuje seznam literatury
The objective of this study was to investigate the relative salt tolerance of four eggplant cultivars (Solanum melongena L.) by studying chlorophyll (Chl) fluorescence parameters during the vegetative growth stage under increasing salinity levels. The plants were grown in pots filled with peat under controlled conditions and were subjected to the salt stress ranging from 0 (control), 20, 40, 80, and 160 mM NaCl for 25 days. The results showed that the increasing NaCl concentration affected hardly the maximum quantum yield of photosystem (PS) II. The quantum yield of PSII (ΦPSII) decreased significantly in ‘Adriatica’ and ‘Black Beauty’ under the salt stress. The photochemical quenching decreased in ‘Black Beauty’ and nonphotochemical quenching increased in ‘Adriatica’ under the salt stress. The Chl fluorescence parameters did not change significantly under the salt stress in ‘Bonica’ and ‘Galine’, revealing their tolerance to salinity. After 25 days of the salt stress, the plant growth was reduced in all cultivars, however, this decline was more pronounced in ‘Adriatica’ and ‘Black Beauty’. Additionally, a significant correlation between the biomass and ΦPSII was observed in ‘Adriatica’ and ‘Black Beauty’. Our results suggest that ΦPSII can be used as a diagnostic tool to identify salt-tolerant egg-plant cultivars., S. Hanachi, M. C. Van Labeke, T. Mehouachi., and Obsahuje bibliografii
A PC-based system with TV input for automatic tracking of a single and contrast object in 2D in a homogeneous and stationary environment has been developed and applied to Morris water maze experiments. Further development of the system aimed at broader support of experiments, reduction of requirements on the stationarity and homogeneity of the scene background and on multiple-object tracking is discussed. The computer control of active light markers of the tracked object applicable to multiple-objects tracking in a time-sharing regime is also mentioned in the conclusion. The latter extension of the system can be applied to kinematic studies in biomechanics, sport and rehabilitation medicine.
A new way of identification of minerals was suggested. The identification was based on chemometric analysis of measured IR spectra of selected minerals. IR spectra were collected using diffuse reflectance technique. The discriminant analysis and principal component analysis were used as chemometric methods. Five statistical models were created for separation and identification of clay minerals. Up to 60 samples of various mineral standards (clay minerals, feldspars, carbonates, sulphates and quartz) from different localities were selected for the creation of statistical models. The results of this study confirm that the discriminant analysis of IR spectra of minerals could provide a powerful tool for mineral identification. Even differentiation of muscovite from illite and identification of mixed structures of illite-smectite were achieved., Michal Ritz, Lenka Vaculíková and Eva Plevová., and Obsahuje bibliografii
Leaf area estimation is an important measurement for comparing plant growth in field and pot experiments. In this study, determination of the leaf area (LA, cm2) in soybean [Glycine max (L.) Merr] involves measurements of leaf parameters such as maximum terminal leaflet length (L, cm), width (W, cm), product of length and width (LW), green leaf dry matter (GLDM) and the total number of green leaflets per plant (TNLP) as independent variables. A two-year study was carried out during 2009 (three cultivars) and 2010 (four cultivars) under field conditions to build a model for estimation of LA across soybean cultivars. Regression analysis of LA vs. L and W revealed several functions that could be used to estimate the area of individual leaflet (LE), trifoliate (T) and total leaf area (TLA). Results showed that the LW-based models were better (highest R 2 and smallest RMSE) than models based on L or W and models that used GLDM and TNLP as independent variables. The proposed linear models are: LE = 0.754 + 0.655 LW, (R2 = 0.98), T = -4.869 + 1.923 LW, (R2 = 0.97), and TLA = 6.876 + 1.813 ΣLW (summed product of L and W terminal leaflets per plant), (R2 = 0.99). The validation of the models based on LW and developed on cv. DPX showed that the correlation between calculated and measured LA was strong. Therefore, the proposed models can estimate accurately and massively the LA in soybeans without the use of expensive instrumentation. and E. Bakhshandeh, B. Kamkar. J. T. Tsialtas
Assessment of soil water repellency (SWR) was conducted in the decomposed organic floor layer (duff) and
in the mineral soil layer of two Mediterranean pine forests, one in Italy and the other in Spain, by the widely-used water
drop penetration time (WDPT) test and alternative indices derived from infiltration experiments carried out by the
minidisk infiltrometer (MDI). In particular, the repellency index (RI) was calculated as the adjusted ratio between
ethanol and water soil sorptivities whereas the water repellency cessation time (WRCT) and the specifically proposed
modified repellency index (RIm) were derived from the hydrophobic and wettable stages of a single water infiltration
experiment. Time evolution of SWR and vegetation cover influence was also investigated at the Italian site. All indices
unanimously detected severe SWR conditions in the duff of the pine forests. The mineral subsoils in the two forests
showed different wettability and the clay-loam subsoil at Ciavolo forest was hydrophobic even if characterized by organic
matter (OM) content similar to the wettable soil of an adjacent glade. It was therefore assumed that the composition
rather than the total amount of OM influenced SWR. The hydraulic conductivity of the duff differed by a factor of 3.8–
5.8 between the two forested sites thus influencing the vertical extent of SWR. Indeed, the mineral subsoil of Javea
showed wettable or weak hydrophobic conditions probably because leaching of hydrophobic compounds was slowed or
prevented at all. Estimations of SWR according to the different indices were in general agreement even if some discrepancies
were observed. In particular, at low hydrophobicity levels the SWR indices gathered from the MDI tests were able
to signal sub-critical SWR conditions that were not detected by the traditional WDPT index. The WRCT and modified
repellency index RIm yielded SWR estimates in reasonable agreement with those obtained with the more cumbersome RI
test and, therefore, can be proposed as alternative procedures for SWR assessment.
Classical Russian pendulum seismometer S-5-S was modified for recording of the rotational components of ground motion around the vertical or horizontal axes; the modified sensor is denoted here as S-5-SR. Experimental field testing of the S-5-SR sensor started in December 2010 in the Karvina coal region that is known as an area of intensive mining induced seismicity. First seismic station was installed in Doubrava village characterized by thick sedimentary layers. Next seismic station was installed in Orlova village, in different local geological conditions, i.e. in region without sedimentary layers. More than 200 mining induced seismic events were recorded on each seismic station during the period of six months of seismic monitoring. The recorded wave patterns confirm the existence of rotational ground motion components in this region; the strongest recorded value of this component exceeded 1 mrad.s-1. Analysis of the obtained records is presented in this paper., Zdeněk Kaláb, Jaromír Knejzlík and Markéta Lednická., and Obsahuje bibliografii
The principles and application prospects of a set-up for simultaneous measurements of oxygen evolution and fluorescence in intact leaves on a fast (10 ms) time scale are descríbed. The oxygen evolution is measured with a photoacoustic technique. The method shows among other things (a) a direct deteimination of the intrinsic yield of 'open' reaction centres (RCs) of photosystem 2 (PS 2), and (b) ihe involvement of a 20-30 % firaction of PS 2 RCs with an apparent low oxygen yield in the light-adapted leaves. Double-flashPS 15 measurements in the light- and dark-adapted leaves have substantiated the absence of inactive RCs in leaves that were kept in the dark for more than 12 h.