This paper focuses on mathematical modeling of high frequency pulsations in pump turbines, which are the source of high-cycle continuous stress of the spiral casing cover, wicket gates and runner. The problem is solved by transfer matrix method. F-A char. and MS Excel programs have been used for data processing. Final results are presented by graphs of frequency-amplitude characteristic depending on running speed of motor, and plots of the pressure mode shape in selected phase shifts. Modeled variants are those of wheels with 7; 9 blades and 7 blades and 7 splitter-blades. The number of distributing blades is 20. and Obsahuje seznam literatury
Mesophyll conductance (gm) is essential to determine accurate physiological parameters used to model photosynthesis in forest ecosystems. This study aimed to determine the effects of time of day on photosynthetic parameters, and to assess the effect of using either intercellular CO2 concentration (Ci) or chloroplast CO2 concentration (Cc), on maximum carboxylation velocity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), Vcmax. We used Amazonian saplings of Myrcia paivae and Minquartia guianensis. Photosynthetic parameters were measured using an infrared gas analyzer (IRGA); gm was determined using both gas exchange and chlorophyll (Chl) a fluorescence and gas-exchange data alone. Leaf thickness (LT) and specific leaf area (SLA) were also measured. Air temperature, relative humidity or understory light did not correlate with gm and on average daily IRGA-fluorometer-determined gm was 0.04 mol(CO2) m-2 s-1 for M. paivae and 0.05 mol(CO2) m-2 s-1 for M. guianensis. Stomatal conductance (gs), gm, electron transport rate (JF), and light-saturated net photosynthetic rate (PNmax) were lower in the afternoon than in the morning. However, no effect of time of day was observed on Vcmax. LT and SLA did not affect any of the examined parameters.
IRGA-determined g m was almost the double of the value obtained using the IRGA-fluorescence method. Vcmax values determined using Cc were about 25% higher than those obtained using Ci, which highlighted the importance of using Cc in Vcmax calculation. Decline in PNmax at the end of the afternoon reflected variations in gs and gm rather than changes in Vcmax. Diurnal variation in gm appeared to be associated more with endogenous than with atmospheric factors. and H. C. S. Nascimento, R. A. Marenco.
A graph is called distance integral (or D-integral) if all eigenvalues of its distance matrix are integers. In their study of D-integral complete multipartite graphs, Yang and Wang (2015) posed two questions on the existence of such graphs. We resolve these questions and present some further results on D-integral complete multipartite graphs. We give the first known distance integral complete multipartite graphs {K_{{p_1},{p_2},{p_3}}} with p1 < p2 < p3, and {K_{{p_1},{p_2},{p_3},{p_4}}} with p1 < p2 < p3 < p4, as well as the infinite classes of distance integral complete multipartite graphs {K_{{a_1}{p_1},{a_2}{p_2},...,{a_s}{p_s}}} with s = 5, 6., Pavel Híc, Milan Pokorný., and Obsahuje seznam literatury