Nowadays we can commonly encounter with revitalizations of an original HPPs which were earlier fitted with Francis turbines. They were often placed to the locations with low head and higher discharge, which means high specific speed (ns > 400). Generally it is quite complex to design Francis turbines for such high specific speed. These very old turbines usually have lower efficiency due to the earlier limited possibilities of hydraulic design. An exchange of a water turbine with another type can be quite expensive and therefore it can be more suitable to change only an old runner for a new one. In this article the design process of high specific speed turbine ns = 430 is described. Optimization was done as the full-automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. For the parameterization of the runner blade, the BladeGen software was used and CFD (Computational Fluid Dynamics) analysis was run in Ansys CFX v.14 software. The final shape runner blade was reached after computing about 1000 variants, which lasted about 250 computational hours. and Obsahuje seznam literatury
Models were developed to estimate nondestructively chlorophyll (Chl) content per unit of leaf area (Chlarea) and nitrogen content per unit of leaf area (Narea) using readings of two optical meters for five warm-temperate, evergreen, broadleaved tree species (Castanopsis sieboldii, Cinnamomum tenuifolium, Eurya japonica, Machilus thunbergii, and Neolitsea sericea). It was determined whether models should be adjusted seasonally. Readings (were obtained six times during a year period and Chlarea and Narea were determined using destructive methods. Bayesian inference was used to estimate parameters of models that related optical meter readings to Chlarea or Narea for each species. Deviance information criterion values were used to select the best among models, including the models with seasonal adjustment. The selected models were species-specific and predicted Chlarea accurately (R2 = 0.93-0.96). The best model included parameters with seasonal adjustments for one out of five species. Model-based estimates of Narea were not as accurate as those for Chlarea, but they were still adequate (R2 = 0.64-0.82). For all species studied, the best models did not include parameters with seasonal adjustments. The estimation methods used in this study were rapid and nondestructive; thus, they could be used to assess a function of many leaves and/or repeatedly on individual leaves in the field. and D. Mizusaki, K. Umeki, T. Honjo.
Chlorophyll (Chl) a fluorescence transient and 820-nm transmission kinetic were investigated to explore the development of photosynthetic apparatus in grapevine leaves from emergence to full expansion. In this study, all leaves at various developing stages exhibited typical Chl a fluorescence transient. In newly initiating leaves, the maximum quantum yield of primary photochemistry (ϕP0) was slightly lower (<10 %) than that in fully expanded leaves. Nevertheless, the fluorescence rise from O to J step was clearly speeded up in young leaves compared with that in fully expanded leaves. Additionally, a distinct K step appeared in young leaves at high irradiances. With leaf development, the efficiency that a trapped exciton can move an electron into the electron transport chain further than QA - (Ψ0), the quantum yield of electron transport beyond QA (ϕE0), electron transport flux per excited cross section (ET0/CS0), the amount of active photosystem (PS) 2 reaction centres per excited cross section (RC/CS0), and the performance index on cross section basis (PICS) increased gradually and rapidly. Young leaves had strikingly lower amplitude of transmission at 820 nm. A linear relationship between Ψ0 and the transmission at 820 nm (I30/I0) was evident. Based on these data, we suggest that (1) the primary photochemistry of PS2 may be not the limiting step of the photosynthetic capacity during leaf growth under natural irradiance; (2) oxygen evolving complex (OEC) might be not fully connected to PS2 at the beginning of leaf growth; (3) though there are a few functional PS1 and PS2 at the early stages of leaf development, they match perfectly. and C.-D. Jiang ... [et al.].
This study presents data about the effect of parent material on the intensity of processes that lead to the formation of a cambic subsurface horizon. The study was performed in the Voděradské bučiny National Nature Reserve with granite bedrock and in Humpolec with paragneiss bedrock. Representative soil profiles in the southeastern part of Bohemia were characterised on a macroscale level based on macromorphological description, particle size distribution, chemical, physical and soil organic matter properties. On the basis of the values of organic carbon and bulk density, the stock of soil organic matter was calculated in the upper 25 cm of soils. A more detailed characteristic of soil cover employed micromorphological and X-ray diffraction analyses. The results revealed differences in the formation of the cambic horizon on different types of parent material. The main soil forming process responsible for the cambic horizon is more intensive at localities with paragneiss bedrock., Anna Žigová, Martin Šťastný and Radka Kodešová., and Obsahuje bibliografii
The development of the nematode Spinitectus inermis (Zeder, 1800), a parasite of the stomach of eels, Anguilla anguilla (L.) in Europe, was experimentally studied. Mayfly nymphs Caenis macrura, Ecdyonurus dispar, Heptagenia sulphurea, Potamanthus luteus and Seratella ignita from Portugal and the Czech Republic were found to serve as experimental intermediate hosts. After ingestion of the nematode eggs by the mayfly nymphs, the toothed first-stage larvae were released and penetrated into the body cavity of the intermediate host. There they moulted twice (on day 4 and 6 post infection [p.i.] at water temperatures of 20-25°C), attaining the third infective stage. The definitive host, A. anguilla, undoubtedly acquires infection by feeding on mayfly nymphs harbouring infective-stage larvae. In an experimentally infected eel, the fourth-stage larva undergoing the third moult was observed 28 days p.i. at water temperature of 20ºC. The larval stages, including moulting forms, are described and illustrated. The prepatent period of S. inermis is estimated to be about two months.
This paper deals with the basic dynamical model of electromotor whose creation motivated by problems of electromotor vibrations and its subsequent fatigue. The model is chaacrterized by a flexible shaft with mounted padket of sheet metals that are equipped with parallel copper bars connected by end shortcircuit rings. Finite element analysis is used for the disretization of the shaft, while the sheet metal packet of cylindrical shape is modelled as a set of rigid bodies joined using chosen viscoelastic forces and torques. The shortcircuit rings are supposed to be rigid in this basic dynamical model and the pieces of copper bars are substituted by massless springs of calculated properties. Problematic model parameters are identified by means of performed experimental modal analysis. and Obsahuje seznam literatury
The aim of this article is to inform reader about the development steps and practices which were used during the development of a control system of a fuel metering pump. The aim of this development was to design a cntrol system for a BLDC motor in accordance with rigid aviation standards and verify new development practices and tools alowing faster and simpler certification. The development covers such steps as definition of first requirements, preliminary design, system modelling and simulation, detailed deisgn, verification and testing. Given description intruduces reader to mandatory practices and procedures which are obligatory for successful certification of developed control systems. In addition, the first results measured on an evaluation sample are presented. and Obsahuje seznam literatury
Philometra overstreeti Moravec et de Buron, 2006 and Philometroides paralichthydis Moravec et de Buron, 2006 are common parasites of the southern flounder, Paralichthys lethostigma Jordan et Gilbert. Because the life cycles of these parasites are unknown, our goal was to assess whether species of copepod commonly found in our estuaries could serve as intermediate hosts for these philometrids. Individuals of five species of copepods were collected and exposed to L1 larvae of each philometrid species. The cyclopoid Oithona colcarva Bowman was the only species to become successfully in-fected. Successive moulting of philometrid larvae in the haemocoel of the copepods was studied using transmission electron microscopy. At 23°C the moult from L1 to L2 was observed for both species as early as 24 h post exposure to L1 larvae. The moult from L2 to L3 was initiated within 2 days post exposure and completed by 6-7 days post exposure. Some parasite-induced tissue damage occurred in the copepod but no cellular response against larval philometrids was observed.
The vibrodiagnostic system VDS-UT2 was developed for the investigation of a tram wheel operational vibration and deformation. The system consists of measuring, acquisition and processing tools for monitoring of tram wheels and their operational parameters, e.g. static and dynamic deformation, displacement, velocity, acceleration and temperature. The measuring on a rotating wheel is realized both by telemetric and by top-timing system. Measured data can be remote-observed via Internet connection with the control PC. The acquisition system by Starmans Electronics s.r.o. provides continuous analog and digital data logging. The control PC processes digital logical signals and evaluates time intervals representing circumferential turning angles between disk and rim.. In the contribution, the diagnostic system is described and the measured data including damage analysis are presented. and Obsahuje seznam literatury
Chrysanthemum plantlets were cultivated in vitro on media with 2.0, 0.3, or 0 % sucrose, or photoautotrophically without an organic carbon source but with supplementation of the culture vessel atmosphere with 2 % CO2. The photoautotrophically cultivated plantlets showed a better growth and multiplication, higher contents of chlorophyll (Chl) and carotenoids, higher Chl a/b ratio, net photosynthetic rate and ribulose-1,5-bisphosphate carboxylase/oxygenase and phosphoenolpyruvate carboxylase activities than plantlets grown on the medium with sucrose. and C. Cristea, F. Dalla Vecchia, N. la Rocca.