Operation of the photovoltaic system in Prague and data evaluation

Received: January 6th, 2021 ; Accepted: April 7th 2021 ; Published: April 12th 2021 ; Correspondence: [email protected] on-grid photovoltaic system was installed at the Faculty of Engineering in 2015. The monitoring system developed in our laboratory monitors data and can also detect failure and type of failure. The evaluation of the data shows that the amount of electricity produced slightly exceeds the expected values predicted by the internationally used internet application PVGIS. The effect of the aging of PV panels has so far had a minimal effect on the electricity produced. Immediate output power is affected by multiple parameters. Higher temperatures reduce the efficiency of energy conversion, so in summer the instantaneous power may be lower even at higher radiation intensity and smaller angle of incidence

Ecological character displacement in the face of gene flow: Evidence from two species of nightingales

<p>Abstract</p> <p>Background</p> <p>Ecological character displacement is a process of phenotypic differentiation of sympatric populations caused by interspecific competition. Such differentiation could facilitate speciation by enhancing reproductive isolation between incipient species, although empirical evidence for it at early stages of divergence when gene flow still occurs between the species is relatively scarce. Here we studied patterns of morphological variation in sympatric and allopatric populations of two hybridizing species of birds, the Common Nightingale (<it>Luscinia megarhynchos</it>) and the Thrush Nightingale (<it>L. luscinia</it>).</p> <p>Results</p> <p>We conducted principal component (PC) analysis of morphological traits and found that nightingale species converged in overall body size (PC1) and diverged in relative bill size (PC3) in sympatry. Closer analysis of morphological variation along geographical gradients revealed that the convergence in body size can be attributed largely to increasing body size with increasing latitude, a phenomenon known as Bergmann's rule. In contrast, interspecific interactions contributed significantly to the observed divergence in relative bill size, even after controlling for the effects of geographical gradients. We suggest that the divergence in bill size most likely reflects segregation of feeding niches between the species in sympatry.</p> <p>Conclusions</p> <p>Our results suggest that interspecific competition for food resources can drive species divergence even in the face of ongoing hybridization. Such divergence may enhance reproductive isolation between the species and thus contribute to speciation.</p

Polyvinyl chloride catheters with repressed migration of plasticizers

Impart flexibility and desired softness of polyvinylchloride (PVC) – one of the most widely used polymeric materials for medical device production – is achieved by addition of appropriate amount of plasticizer, usually di(2-ethylhexyl phthalate) (DEHP), into polymer matrix. DEHP is not chemically bonded to PVC and migrates to the surrounding media such as saliva, blood, plasma, or serum resulting in several toxic effects. Migration of DEHP can be significantly suppressed by embedding PVC into another polymer preventing its direct contact with surrounding liquid media. Coextruded TPU-PVC-TPU catheters were prepared with various thicknesses of TPU layers to evaluate its repressing effect on DEHP releasing. Releasing kinetic of DEPH from both three layered catheters and PVC catheters into the acetonitrile was observed in various time intervals and determined using reverse-phase liquid chromatographic technique

Impact of environmental factors to wheat ethanol production in the conditions of Central Europe

Wheat with its advantages of high yield stability, well-mastered crop management and the possibility of long-term storage is suitable for ethanol production. Ethanol production has to be cost-effective and, therefore, wheat used in production should have a high potential for ethanol production. Previous works showed that low-nitrogen grain content is important for the relative ethanol yield and the agronomic yield for the absolute ethanol yield per area is important. In this work, importance of grain nitrogen and starch content for ethanol conversion efficiency was verified. Furthermore, environmental effects in relation to the ethanol conversion efficiency and ethanol yield in conditions of Central Europe were studied. With regard to the environmental factors, the annual rainfall sum was found to be the most important factor for ethanol conversion efficiency, while the grain yield was found to be the most important factor for the ethanol yield. On the basis of these findings it can be considered that wheat varieties possessing high yields of low protein grain planted in areas with higher rainfall amount would be ideal for the production of ethanol

Development of a molecular marker for simultaneous selection of Rph7 gene and effective Mla alleles in barley

Barley ( Hordeum vulgare L.) is one of the most economically important crops around the world. Diseases caused by fungi and viruses significantly reduce yield. The most important fungal diseases are leaf rust caused by Puccinia hordei , and powdery mildew caused by Blumeria graminis f. sp. hordei . The most economical and ecologically friendly way to avoid losses caused by these diseases is growing resistant varieties. Concerning practical breeding for powdery mildew and leaf rust resistance, simple, cheap and robust selection methods are required. Marker assisted selection (MAS) is of great potential to fulfil this demand. In this paper, we present development of a robust duplex marker for simultaneous selection of Rph7 , and presence of one of the following Mla alleles: Mla16, Mla19, Mla20, Mla21, Mla27 or Mla28

Prediction of wheat baking quality using reomixer analysis of whole-grain meal

A 10-gram computerised mixograph-based Reomixer instrument was used to analyse eight bread wheat cultivars. The influence of flour or whole-grain meal and different hydration methods for whole-grain meal on the prediction of baking quality was studied. Using flour/whole-grain meal materials and different hydration methods, several Reomixer parameters were found to correlate with bread-making performance. Regression equations were constructed using statistically significant Reomixer parameters. Whole-grain meal Reomixer analysis under constant hydration of 75% proved to be as comparable a method for bread-making performance evaluation as flour analysis

Experimental and numerical evaluation of composite part strength

project FV30033 of the Ministry of Industry and Trade of the Czech Republic and by the Grant Agency of the Czech Technical University in Prague, under grant No. SGS18/175/OHK2/3T/1

Development of composite element joining keel beam and aircraft fuselage

This work has been supported by project FV30033 of the Ministry of Industry and Trade of the Czech Republic and by the Grant Agency of the Czech Technical University in Prague, under grant No. SGS21/151/OHK2/3T/1

Subgrain formation during deformation: physical origin and consequences

International audienceThe formation of subgrains in the course of plastic deformation is explained as a result of a trend to make the deformation easier by locally reducing the number of active slip systems. Local preference of one slip system changes the crystal orientation with respect to stress (Schmid factor), thus leading to geometrical softening or hardening. The trend to subgrain formation is treated in the framework of continuum mechanics as an instability against internal bending for the simple case of a crystal originally oriented for symmetric double slip. Once formed, the boundaries of the subgrains lead to hardening as they induce long-range internal back stresses in the interior of the subgrains by forcing the mobile dislocations to take a bowed configuration. Simple dislocation-based and Cosserat models are recalled to explain the size-dependent subgrain hardening, where smaller subgrains are stronger