Safe and effective loading of nuclear reactor fuel assemblies demand qualitative and quantitaive analysis of the relations between the coolant temperature in the fuel assembly outlet, measured by a thermocouple, and the mean temperature of the coolant in the thermocouple plane position. In the laboratory at the Institute of Thermal Power Engineering of the Slovak University of Technology in Bratislava, an experiemental physical fuel assembly model of the VVER 440 nuclear power plant with V 213 nuclear reactors was installed The aim of the measurements on the physical model was to analyze the temperature and velocity profiles in the fuel assembly outlet. The following article deals with the analyses of these measurements based on different mass flow of the water through a physical model of the fuel assembly outlet. The following arficle deals with the analysis of these measurements based on different discontinuity generated by cold water flowing through triplet tubes and central tube in plane 1, and the positioning of the mixing CFD grid simulations of a fuel assembly outlet. All analyses were validated by means of measurements on the physical model of the fuel assembly. and Obsahuje seznam literatury
We studied the diet of 10 species of grasshopper belonging to the family Pamphagidae over a period of 3 years at 6 localities in North Eastern Algeria. The species of plants consumed by the grasshoppers was determined by comparing slide mounted specimens of the pieces of plant epidermis in their faeces with those in a reference collection of identified plants collected from the same localities. The percentages of occurrence of the different species of plants in the faeces of the grasshoppers were not related to the abundance of the plants at the sites studied. All the grasshoppers were polyphagous but differed in the percentage of Poaceae in their diets. The diet of Tmethis and Ocneridia contained a higher percentage of Poaceae than the other species and are considered to be ambivores. The three species in the Pamphagus gr. djelfensis complex differ in their diets but all tend to avoid consuming Poaceae and are categorized as forbivores. We also compared the frequency of occurrence of Fabaceae in the faeces and in the field and O. volxemii is the only species that avoided consuming this plant family. The number of sensilla on the labrum was also studied in both sexes of each species. Once one corrects for differences in the size of the labrum, the forbivores have higher numbers of sensilla in groups A1, A2 and A3 (but not A10) than the ambivores. The numbers of sensilla in the A10 group on the labrum of species of Pamphagidae is greater than on that of species of Acrididae, which are mainly graminivores and adapted to semi-arid conditions., Naima Benkenana, Abboud Harrat, Daniel Petit., and Obsahuje seznam literatury
This paper deals with the species composition of epiphytic lichens in Central European oak forests. A total of 192 oak trees at 48 localities in the Czech Republic, Slovakia and Hungary were investigated. In total, 104 lichen species were recorded and divided into three groups in accordance with their frequency of occurrence on trees within the area. The importance of abiotic factors affecting species composition was assessed by multivariate statistics. Principal component analysis illustrated that lichen assemblages reflected geographical distribution of localities and that the occurrence of many species is closely associated with several environmental factors. In particular there is a high negative association with pollution, and positive associations with precipitation, solar radiation and basic bedrock. The variation partitioning estimated the influence of environmental parameters, human impact and naturality factors on lichen composition. Cluster analysis recognized six communities of lichens, of which the members differed from those in the other communities in their autecological characteristics. Two of the communities can be assigned to Parmelion caperatae and Pertusarion amarae and seem to be similar to natural lichen communities of oak forests in Central Europe. Possible reasons for absence of several epiphytic lichen associations (Lobarion pulmonariae, Pertusarion hemisphaericae) in the forests studied is discussed and the species composition in Central Europe was compared with the lichen assemblages in oak forests in neighbouring regions (western Europe, Scandinavia). On the basis of these findings several indicative species of close to natural oak forest are suggested (Acrocordia gemmata, Bacidia rubella, Calicium spp., Caloplaca lucifuga, Cetrelia olivetorum s.l., Chrysothrix candelaris, Flavoparmelia caperata, Melanelia subargentifera).
The article deals with the posssibility of using different design techniques of centrifugal pumps designing in the context of their use in the computer-aided design. It is carried out a comparison of calculated and experimental pump characteristics. and Obsahuje seznam literatury
High temperature alters the internal microstructure of rocks and consequently changes the physical and mechanical properties of rocks. Many studies have been carried out to examine the transformations in the microstructures of rocks under high temperature through near infrared spectroscopy (NIR), Raman spectroscopy, or thermo gravimetric analysis (TGA). The current review synthesizes the data from a number of literatures and summarizes the major transformations of silica rocks under high temperature. The analysis shows that silica rocks starts to lose the water adsorbed in open pores upon heating at about 150 °C. At 200-300 °C, the reaction between SiOH (silanole) in the rocks generates new Si-O-Si bonds as well as H2O, and decreases the open pores. The rocks undergo volume expansion at >550 °C, and the volume contracts and forms new micro pores or cracks which play an important role in the evacuation of the water., Jishi Geng, Qiang Sun, Yuchun Zhang and Yuliang Zhang., and Obsahuje bibliografické odkazy
The previously developed thoracic finite element model [8, 9] was used to investigate the human thoracic dynamic responses associated with the frontal, lateral and oblique loading and to predict injuries of the thorax associated with the frontal loading. The thoracic model was developed [8, 9] to improve the human articulated rigid body model ROBBY (the model of an average adult male) [13, 14], which was previously developed at the University of West Bohemia in cooperation with ESI Group (Engineering Simulation for Industry). There are implemented deformable models of the thorax and abdomen in the ROBBY model. The geometries of individual thoracic organs were based on the cadaver tomography data and color cross-section photographs obtained from Visible Human Project (VHP) [33]. The thoracic model material properties were obtained either by virtue of cooperation with ESI Group or from public sources (articles, Internet, books). Thoracic model includes the models of the sternum, ribs, costal cartilages, vertebrae, lungs, heart, trachea, main vessels (aorta, vena cava superior), intercostal muscles, diaphragm, flesh and skin. The presented study deals with the dynamic response and validation of the whole thoracic model and with the prediction of thoracic injuries by virtue of this model. The results of simulations are compared with the experimental results. and Obsahuje seznam literatury
DNA barcoding surveys of small insects usually extract DNA from either a complete insect or a leg. Little is known about how to optimize DNA quantity and quality from different insect parts while preserving a morphological voucher. Here, we quantify DNA yield from different body parts (antenna, hind leg, forewing, hind wing and abdomen) of the micro-moth Cameraria ohridella (Lepidoptera: Gracillariidae) using fluorescent nucleic acid stain (PicoGreen). Samples were preserved in 100% ethanol or dried for three weeks. Our experiment was designed to encompass practical sampling options during fieldwork. DNA quality was assessed by PCR amplification of the mitochondrial COI barcode fragment. In addition, we compared PCR amplification using Platinum® Taq and Qiagen DNA Polymerase and quantified sequence success of amplified DNA. We show that overall, dry parts showed higher eluted DNA yields. PCR and sequencing success rate were slightly higher for dry tissue than ethanol-preserved parts. We also show that Platinum® Taq yielded the highest PCR success rate and that all dry tissues are sequenceable. The optimal strategy for DNA barcoding surveys is therefore to mount micro-Lepidoptera specimens in the field for morphological analysis and sample tissues (hind legs are favoured) from dried samples at a later time (several weeks) in the lab for DNA barcoding using preferentially Platinum® Taq. If larger amounts of DNA are required (i.e. for nuclear gene sequencing), several legs from one side of the specimen or the abdomen should be preserved in pure ethanol., Carlos Lopez-Vaamonde ... [et al.]., and Obsahuje seznam literatury