Browse

You are looking at 101 - 110 of 90,128 items

Open access

Zeqir Hashani, Qenan Maxhuni, Rrahman Ferizi, Almir Abdurrahmani and Xhavit Mala

Abstract

Flora of the southern part of Kosovo has previously been studied in a limited way due to the difficult terrain and the fact that up to the 1990s it was a military area. In this paper we report Galanthus elwesii Hook for the first time from Kosovo. This species is found in different habitats, mainly in siliceous substrate or wet meadows of the Dragash Municipality, South Kosovo. This species was collected in the Vraça Mountains, near Restelica, (part of National Park ‘Sharri’) on the road leading to the border with Macedonia. The study area consists of territories belonging to the phytogeographic system Skardon-Pindik (Sharri-Pindi) and includes the mountain ranges of Sharri. This research comprises the presence, description, spread and mapping of the species.

Open access

Jun Wang, Yifan Wu, Jueyi Sui and Bryan Karney

Abstract

Ice jams in rivers often arise from the movement of frazil ice as cover-load under ice cover, a process which is conceptually similar to the movement of sediment as bed-load along a river bed. The formation and movement of an ice-accumulation wave is one facet of a larger class of cover-load movements. The movement of an ice-accumulation wave obviously plays a crucial role in the overall process of ice accumulation. In the present study, experiments under different flow and ice conditions help reveal the mechanics of formation and evolution of ice-accumulation waves. In particular, suitable criteria for formation of an ice-accumulation wave are investigated along with the resulting speed of wave propagation. The transport capacity of frazil ice under waved accumulation is modeled by comparing those of experiments collected in laboratories, and the resulting equation is shown to be in good agreement with measured experimental results.

Open access

Rudolf Navrátil, Yvonne Brodrechtová, Róbert Sedmák and Ján Tuček

Abstract

Scenarios modelling offers to forest management an option how to envision complex future associated with various natural, social, or economic uncertainties. The challenge is what modelling method to choose as many methodological approaches to scenario building exists. Morphological analysis is a basic modelling method for structuring and analysing a whole set of relationships existing in multi-dimensional, non-quantifiable, and complex topics. Especially, its application is relevant when abstract policy or market-driven challenges need to be investigated. In this study, we demonstrated the usefulness of the morphological analysis with an example case taken from forest management in Slovakia. The use of the method has enabled, from a number of uncertain futures, to identify three possible, plausible and consistent future scenarios of possible forest management direction in the regions of Podpoľanie and Kysuce. Additionally, the future scenario modelling as prognostic method of qualitative research supported by quantitative models or forestry DSS could introduce participation and more dimensions into forest management modelling. Thus, the future scenarios modelling offers new methodological possibilities to how to deal with increasing uncertainties associated with increasing demands for various ecosystem services or negative impacts of climate change, that forest management in Slovakia will face in the near future.

Open access

Mahsa Jahadi, Hossein Afzalimehr and Paweł M. Rowinski

Abstract

Investigation of the interactions between submerged vegetation patch and flow structure is of crucial importance for river engineering. Most of hydraulic models have been presented for fully developed flows over uniform vegetation in the laboratory conditions; however, the mentioned interactions are complex in river flows where the flow is not developed along small patch. This reveals a gap between developed and non-developed flow along the vegetation patch. This study was conducted in a gravel-bed river in the central Iran. The results reveal that the flow structure in evolving flow (non-developed flow) along the patch resembles that in shallow mixing layer. Accordingly, a shallow mixing layer model and modified equations are combined to quantify evolving area along the patch. The evolving shallow mixing layer equations for the flow along a non-uniform vegetation patch reach a reasonable agreement with field data. However, the spreading coefficient of this model less than one was reported in literature, 0.06 and 0.12. In addition, the flow immediately downstream the vegetation patch behaves similar to a jet and is parameterized by two conventional models, conventional logarithmic law and mixing layer theory. These models present a reasonable agreement with the measured velocity profiles immediately downstream the patch.

Open access

O. Košulič and Š. Mašová

Summary

Details about the record of a juvenile mermithid roundworm parasitizing the bark spider Caerostris sumatrana Strand, 1915 from Thailand are presented. The morphology and ecology of both organisms is discussed. Morphological features suggest this juvenile nematode belongs to the genus cf. Aranimermis. Due to the subadult stage of parasite, identification to species-level was not possible. This first report of a nematode infection in C. sumatrana with several recent findings from other studies significantly adds to the current inventory of mermithids parasitizing spiders. Moreover, our finding is among the first record of this host-parasite interaction from Southeast Asia.

Open access

Lemnaouar Zedam, Mourad Yettou and Abdelaziz Amroune

Abstract

In a recent paper, Çeven and Öztürk have generalized the notion of derivation on a lattice to f-derivation, where f is a given function of that lattice into itself. Under some conditions, they have characterized the distributive and modular lattices in terms of their isotone f-derivations. In this paper, we investigate the most important properties of isotone f-derivations on a lattice, paying particular attention to the lattice (resp. ideal) structures of isotone f-derivations and the sets of their f-fixed points. As applications, we provide characterizations of distributive lattices and principal ideals of a lattice in terms of principal f-derivations.

Open access

Balázs Bodnár and György Csomós

Abstract

In the EU programming period of 2014–2020, Hungary’s largest-ever transport development project, an intermodal passenger terminal (IPT), is planned to be built in Debrecen. The IPT will integrate all public transport modes operating in Debrecen in a single building, with the modes being as follows: railways, long-distance and local buses, trolley-buses and trams. In addition, by creating a large number of parking spaces for cars, and by building lanes for bicycles and pedestrians heading into the facility, the public transport and individual transport modes will be directly connected under the roof of the IPT. The IPT development will be accompanied by large-scale urban renewal projects to revitalise Petőfi square, one of Debrecen’s major public spaces, lying in front of the building. Relating to the IPT development, several feasibility studies and sustainability analyses have been performed; however, the impact of the IPT on the development of Debrecen has not previously been examined. The main goal of this paper is to examine whether IPT development contributes to the enhancement of Debrecen’s central position in its agglomeration, the strengthening of Debrecen’s competitiveness in Hungary’s urban system, the spatial decentralisation of the city’s cultural activities and how it may influence the change of Debrecen’s socio-economic factors.

Open access

Pavel Vlasák, Zdeněk Chára, Václav Matoušek, Jiří Konfršt and Mikoláš Kesely

Abstract

For the safe and economical design and operation of freight pipelines it is necessary to know slurry flow behaviour in inclined pipe sections, which often form significant part of pipelines transporting solids. Fine-grained settling slurry was investigated on an experimental pipe loop of inner diameter D = 100 mm with the horizontal and inclined pipe sections for pipe slopes ranging from −45° to +45°. The slurry consisted of water and glass beads with a narrow particle size distribution and mean diameter d50 = 180 µm. The effect of pipe inclination, mean transport volumetric concentration, and slurry velocity on flow behaviour, pressure drops, deposition limit velocity, and concentration distribution was studied. The study revealed a stratified flow pattern of the studied slurry in inclined pipe sections. Frictional pressure drops in the ascending pipe were higher than that in the descending pipe, the difference decreased with increasing velocity and inclination. For inclination less than about 25° the effect of pipe inclinations on deposition limit velocity and local concentration distribution was not significant. For descending pipe section with inclinations over −25° no bed deposit was observed.

Open access

Snežana Vuksanović, Nada Bubanja and Christian Berg

Abstract

During floristic research of acidic bogs, calcareous fens and seasonally flooded (periodically inundated) grassy places in beech forests in Semolj region, Eleocharis carniolica W. D. J. Koch was found, which was the first record of that species in vascular plant flora of Montenegro. In surrounding countries, this species was recorded in Bosnia and Herzegovina, Croatia, Slovenia and Albania. This paper provides description of sites, habitat and ecology of Eleocharis carniolica W. D. J. Koch in Montenegro.

Open access

Nihal Kuzu and Ekrem Cicek

Abstract

As radiation science and technology advances, nuclear medicine applications are increasing worldwide which necessitate the understanding of biological implications of such practices. Ionizing radiation has been shown to cause degraded matrix and reduced proteoglycan synthesis in cartilage, and the late consequences of which may include degenerative arthritis or arthropathy. Although degenerative effects of the ionizing radiation on cartilage tissue have been demonstrated, the effects on the mechanical properties of articular cartilage are largely unknown. The radiopharmaceuticals, technetium-99m and technetium-99m sestamibi, were utilized on bovine articular cartilage to investigate these effects. We used two different mechanical tests to determine the mechanical properties of articular cartilage. Dynamic and static mechanical tests were applied to calculate compressive modulus for articular cartilage. We observed clearly higher control modulus values than that of experimental groups which account for lesser stiffness in the exposed cartilage. In conclusion, compressive moduli of bovine articular cartilage were found to decrease after radiopharmaceutical exposure, after both instantaneous and equilibrium mechanical experiments.