The objective of this paper is to simulate flow frequency distribution curves for Amazon catchments with the aim of scaling power generation from small hydroelectric power plants. Thus, a simple nonlinear rainfall-runoff model was developed with sigmoid-variable gain factor due to the moisture status of the catchment, which depends on infiltration, and is considered a factor responsible for the nonlinearity of the rainfall-runoff process. Data for a catchment in the Amazon was used to calibrate and validate the model. The performance criteria adopted were the Nash-Sutcliffe coefficient (R²), the RMS, the Q95% frequency flow percentage error, and the mean percentage errors ranging from Q5% to Q95%.. Calibration and validation showed that the model satisfactorily simulates the flow frequency distribution curves. In order to find the shortest period of rainfall-runoff data, which is required for applying the model, a sensitivity analysis was performed whereby rainfall and runoff data was successively reduced by 1 year until a 1.5-year model application minimum period was found. This corresponds to one hydrological year plus the 6-month long ''memory''. This analysis evaluates field work in the ungauged sites of the region. and Cieľom tohto príspevku je simulácia čiar rozdelenia prietokov pre povodia rieky Amazonka pre potreby hodnotenia premeny energie v malých hydroelektrárňach. Preto bol vyvinutý jednoduchý nelineárny zrážko-odtokový model so sigmoidálne sa meniacim zdrojovým faktorom v závislosti od obsahu vody v povodí, ktorý závisí od infiltrácie a je považovaný za faktor, spôsobujúci nelinearitu zrážkoodtokových procesov. Pre kalibráciu a validizáciu modelu boli použité údaje z povodí rieky Amazonka. Použili sme tieto hodnotiace kritériá: Nashov-Sutcliffov koeficient (R²), RMS, Q95%, chyba určenia odtoku v percentách, a priemerná percentuálna chyba v rozsahu od Q5% do Q95%. Kalibrácia a validizácia ukázala, že model simuluje čiary rozdelenia prietokov uspokojivo. Aby bolo možné nájsť najkratšie obdobie pre nájdenia závislosti zrážky - odtok, ktorá je potrebná pre aplikáciu v modeli, použili sme citlivostnú analýzu tak, že údaje zrážky - odtok boli postupne redukované o jeden rok, až kým nebolo nájdené minimálne obdobie pre aplikáciu vzťahu zrážky - odtok 1,5 roka. Toto obdobie zodpovedá jednému hydrologickému roku, plus 6 mesiacov dlhá ''pamäť''. Touto analýzou boli vyhodnotené výsledky terénnych meraní v oblastiach, kde neboli k dispozícii merania odtoku.
Controversial aspects of the conventional and widely used concept of the integral vortex strength are briefly discussed. The strength of a vortex is usually calculated as the circulation along the vortex boundary, or equivalently due to Green’s theorem, as the surface integral of vorticity over the planar vortex cross section. However, the local effect of an arbitrary ''superimposed shear'' is fully absorbed by vorticity what makes the circulation a shear-biased vortex characteristic. The present paper shows that different vortexstrength models can be derived on the basis of different local vortex intensities proposed in the literature. The outcome of these models naturally differs, even for an ideally axisymmetric vortex. Three different vortex-strength models are compared and discussed by examining the unsteady Taylor vortex. and V práci jsou stručně diskutovány sporné stránky konvenčního a široce užívaného pojetí integrální síly víru. Síla víru je obvykle počítána jako cirkulace podél hranice víru nebo ekvivalentně podle Greenovy věty jako plošný integrál vířivosti přes příčný rovinný řez vírem. Lokální efekt libovolného ''superponovaného smyku'' je však plně absorbován vířivostí, což činí z cirkulace smykově zkreslenou vírovou charakteristiku. Tento článek ukazuje, že lze odvodit různé modely síly víru na základě různých lokálních intenzit víru navržených v odborné literatuře. Výsledky těchto modelů se přirozeně liší, dokonce i pro ideálně osově symetrický vír. Na podkladě zkoumání nestacionárního Taylorova víru jsou porovnány a diskutovány tři různé modely síly víru.
The aim of the present work was to study the effect of 3- mercapto-5H-1,2,4-triazino[5,6-b]indole-5-acetic acid (CMTI), an efficient aldose reductase inhibitor, on sorbitol accumulation in selected organs of streptozotocin-induced diabetic rats in vivo . In addition, the effect of CMTI on aldose reductase back reaction and on sorbitol dehydrogenase was determined. The model of experimental diabetes in male Wistar rats induced by streptozotocin was used. Experimental diabetes was induced by triple intraperitoneal doses of streptozotocin on three consecutive days. In diabetic rats, significant elevation of sorbitol concentration in the sciatic nerve and eye lenses was recorded. CMTI administered intragastrically (50 mg/kg/day) for five consecutive days significantly inhibited sorbitol accumulation in the sciatic nerve, yet it was without effect in eye lenses of diabetic animals. For aldose reductase back reaction, the substrate affinity of glycerol to aldose reductase was one order lower than that of glyceraldehyde in forward reaction. In addition, the back reaction was much slower, characterized by Vmax value of about 30 times lower than that of the forward reaction. Inhibition of aldose reductase by CMTI was characterized by closely related IC50 values in submicromolar range for both forward and back reactions. No significant inhibition of the second enzyme of the polyol pathway, sorbitol dehydrogenase, by 100 μM CMTI was recorded (I=0.9±2.7 %, n=3). To conclude, the presented results showed the ability of CMTI to affect the polyol pathway in diabetic rats in vivo and represent thus a further step in a complex preclinical evaluation of CMTI as a potential agent for treatment of chronic diabetic complications., M. Soltesova Prnova, J. Ballekova, A. Gajdosikova, A. Gajdosik, M. Stefek., and Obsahuje bibliografii
This paper presents idea flow, development and construction of an anthropomorphic hand which is intended to be used mainly in prosthetics. Fundamental results of simulations and optimization of grasp are shown. The prototype has been manufactured and the principal functionality of finger mechanism (drive three axes by one string) has been tested. A new mechanical principle has been developed which is based again on an idea of using less actuators then joints with keeping adaptability and functionality of the mechanism. and Obsahuje seznam literatury
The development of smartphones, specifically their cameras, and imaging technologies has enabled their use as sensors/measurement tools. Here we aimed to evaluate the applicability of a fast and noninvasive method for the estimation of total chlorophyll (Chl), Chl a, Chl b, and carotenoids (Car) content of soybean plants using a smartphone camera. Single leaf disc images were obtained using a smartphone camera. Subsequently, for the same leaf discs, a Chl meter was used to obtain the relative index of Chl and the photosynthetic pigments were then determined using a classic method. The RGB, HSB and CIELab color models were extracted from the smartphone images and correlated to Chl values obtained using a Chl meter and by a standard laboratory protocol. The smartphone camera was sensitive enough to capture successfully a broad range of Chl and Car contents seen in soybean leaves. Although there was a variation between color models, some of the proposed regressions (e.g., the S and b index from HSB and Lab color models and NRI [RGB model]) were very close to the Chl meter values. Based on our findings, smartphones can be used for rapid and accurate estimation of soybean and Car contents in soybean leaves., J. P. G. Rigon, S. Capuani, D. M. Fernandes, T. M. Guimarães., and Obsahuje bibliografii
In passing remarks, some commentators have noted that for Nagel, physicalism is true. It has even been argued that Nagel seeks to find the best path to follow to achieve future physicalism. I advance these observations by adding that for Nagel, we should discuss the consciousness problem not in terms of physical and mental issues but in terms of our desire to include consciousness in an objective/scientific account, and we can achieve this only by revising our self-conception, i.e., folk psychology, to develop a more detached view of experience. Through the project of objective phenomenology, Nagel aims to achieve some sort of objective, detached, and scientific explanation of the subjective nature of experience. This project seeks to make the truth of physicalism intelligible and consciousness more amenable to scientific study, potentially raising an even broader concept than the one physicalism originally proposes.
Steady two-dimensional natural convection taking place in a rectangular cavity, partially filled with an isotropic porous material, has been investigated numerically using an ADI method. It is assumed that one of the vertical walls of the cavity has a ramped temperature distribution. The vorticity-stream function formulation has been used to solve the set of nonlinear partial differential equations governing the flows in the clear region and the adjoining porous region. The effects of Darcy number and Rayleigh number have been discussed in detail.
The aim of this paper was to demonstrate that it is possible to control the chaos into the Sherman system by linear feedback of own signals. After introducing of the parameter ‘α‘ in the z-equation (α → α + α1 x(t) + α2 y(t) + α3 z(t), we study how the global dynamics can be altered in a desired direction (αn are considered as free parameters). We make a detailed bifurcation investigation of the modified Sherman systems by varying the parameters αn. Finally, we calculate the maximal Lyapunov exponent, where the chaotic motion of modified Sherman system exists. and Obsahuje seznam literatury
In endoprosthesis surgery there are typically a high percentage of implant defects, these can lead to failure of the whole prosthesis. One type of total hip replacement function loss is acetabular cup loosening from the pelvic bone. This article examines manufacture perturbations as one of the possible reasons for this kind of failure. Both dimension and geometry manufacturing perturbations of ceramic head and polyethylen cup were analyzed. We find that perturbations in the variables analysed here affect considered values of contact pressure and frictional moment. Furthermore, contact pressure and frictonal moment are quantities affecting replacement success and durability. From obtained results we can recommend to fit head and cup with a clearance of between 0 mm andd 0.05 mm. We do not recommend using interference type of fit. Roundness perturbation of ceramic head should not exceed 0.025 mm. and Obsahuje seznam literatury