Weighing lysimeters can be used for studying the soil water balance and to analyse evapotranspiration (ET). However, not clear was the impact of the bottom boundary condition on lysimeter results and soil water movement. The objective was to analyse bottom boundary effects on the soil water balance. This analysis was carried out for lysimeters filled with fine- and coarse-textured soil monoliths by comparing simulated and measured data for lysimeters with a higher and a lower water table. The eight weighable lysimeters had a 1 m2 grass-covered surface and a depth of 1.5 m. The lysimeters contained four intact monoliths extracted from a sandy soil and four from a soil with a silty-clay texture. For two lysimeters of each soil, constant water tables were imposed at 135 cm and 210 cm depths. Evapotranspiration, change in soil water storage, and groundwater recharge were simulated for a 3-year period (1996 to 1998) using the Hydrus-1D software. Input data consisted of measured weather data and crop model-based simulated evaporation and transpiration. Snow cover and heat transport were simulated based on measured soil temperatures. Soil hydraulic parameter sets were estimated (i) from soil core data and (ii) based on texture data using ROSETTA pedotransfer approach. Simulated and measured outflow rates from the sandy soil matched for both parameter sets. For the sand lysimeters with the higher water table, only fast peak flow events observed on May 4, 1996 were not simulated adequately mainly because of differences between simulated and measured soil water storage caused by ET-induced soil water storage depletion. For the silty-clay soil, the simulations using the soil hydraulic parameters from retention data (i) were matching the lysimeter data except for the observed peak flows on May, 4, 1996, which here probably resulted from preferential flow. The higher water table at the lysimeter bottom resulted in higher drainage in comparison with the lysimeters with the lower water table. This increase was smaller for the finer-textured soil as compared to the coarser soil.
This paper is concerned with Francis water turbine power control issue. There are introduced six conceptions of power controllers and corresponding control loop features are discussed. The control features are illustrated with step responses and the major attention is paid to the undesirable under-control effect. On an example of control system with an elementary description and with relatively short turbine pipeline feeder are the control features compared. and Obsahuje seznam literatury
Responses to drought were studied using two maize inbred lines (B76 and B106) and a commercial maize hybrid (Zea mays L. cv. Silver Queen) with differing resistance to abiotic stress. Maize seedlings were grown in pots in controlled environment chambers for 17 days and watering was withheld from one half the plants for an additional 11 days. On the final treatment date, leaf water potentials did not differ among genotypes and were -0.84 and -1.49 MPa in the water sufficient and insufficient treatments, respectively. Greater rates of CO2 assimilation were retained by the stress tolerant maize inbred line, B76, in comparison to the other two genotypes 11 days after watering was withheld. Rates of CO2 assimilation for all three genotypes were unaffected by decreasing the measurement O2 concentration from 21 to 2% (v/v). Activities of phosphoenolpyruvate carboxylase (PEPC), NADP-malic enzyme (NADP-ME), and NADP malate dehydrogenase were inhibited from 25 to 49% by the water deficiency treatment. Genotypic differences also were detected for the activities of NADP-ME and for PEPC. Changes of transcript abundance for the three C4 pathway enzymes also varied among watering treatments and genotypes. However, examples where transcripts decreased due to drought were associated with the two stress susceptible genotypes. The above results showed that enzymes in the C4 photosynthetic pathway were less inhibited by drought in stress tolerant compared to stress susceptible maize genotypes., R. Sicher, J. Bunce, J. Barnaby, B. Bailey., and Obsahuje bibliografii
Effects of water and nitrogen (N) supply on growth and photosynthetic response of B. carinata were examined in this study. Plant growth and related characteristics varied significantly in response to the availability of water and nitrogen. B. carinata maximized the utilization efficiency of the most limiting resources by developing physiological adaptations, such as changes in root and leaf development. The utilization of water and N was tightly linked with the availability of each resource. Instantaneous water-use efficiency (WUE) was always greater in plants with high-N nutrition [50, 100, and 150 kg(N) ha-1] than in the low-N-treated plants
[0 kg(N) ha-1] in all watering treatments. Instantaneous N-use efficiency (PNUE) decreased significantly with increasing water stress in all N treatments. Seed yield is significantly related to PNUE (p>0.05) but not WUE (p<0.05). The positive relationship between leaf net photosynthetic rate (PN) and seed yield suggests that PN can be used as an important tool for selection of new strains with high seed yield. and X. Pan ... [et al.].
Environmental conditions that promote photorespiration are considered to be a major driving force for the evolution of C4 species from C3 ancestors. The genus Flaveria contains C3 and C4 species as well as a variety of intermediate species. In this study, we compare the water-use efficiency of intermediate Flaveria species to that of C3 and C4 species. The results indicate that under both well-watered and a drought-stress condition, C3-C4 and C4-like intermediacy in Flaveria species improve water-use efficiency as compared to C3 species. and M. C. Dias, W. Brüggemann.
The uniqueness theorem is proved for the linearized problem describing radiation and scattering of time-harmonic water waves by a vertical shell having an arbitrary horizontal cross-section. The uniqueness holds for all frequencies, and various locations of the shell are possible: surface-piercing, totally immersed and bottom-standing. A version of integral equation technique is outlined for finding a solution.
A multi-head 1-way pushdown automaton with k heads is a pushdown automaton with k 1-way read heads on the input tape and a stack. It was previously shown that the deterministic variant of the model cannot accept all the context free languages. In this paper, we introduce a 2-tape, 2-head model namely Watson-Crick pushdown automata where the content of the second tape is determined using a complementarity relation, similar to Watson-Crick automata. We show computational powers of nondeterministic two-head pushdown automata and nondeterministic Watson-Crick pushdown automata are same. Moreover, deterministic Watson-Crick pushdown automata can accept all the context free languages.
Paper summarizes the results in the area of information physics that is a new progressively developing field of study trying to introduce basics of information variables into physics. New parameters, like wave information flow, wave information/knowledge content or wave information impedance, are first defined and then represented by wave probabilistic functions. Next, relations between newly defined parameters are used to compute information power or to build wave information circuits covering feedbacks, etc.
The paper presents the basic theory of wave probabilistic models together with their features. By introduction of the complementarity's principle between x-representation and k-representation the probability theory is completed for "structural" parameter which carries information about the changes of time series or random processes. The next feature of wave probabilistic models is the quantization principle or definition of probabilistic inclusion-exclusion rules.
The paper continues with the theory of wave probabilistic models and uses the inclusion-exclusion rule to describe quantum entanglement as a wave probabilities resonance principle. The achieved results are mathematically described and an illustrative example is shown to demonstrate the possible applications of the presented theory.