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  • Author: István Nagy x
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Monitoring of Polycyclic Aromatic Hydrocarbons (Pahs) in Surface Water of the Hungarian Upper Section of the Danube River

The aim of this paper is to investigate the concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface water of the Hungarian upper section of the Danube River in the period of 2007-2010. A total of 77 water samples were collected from the sampling sites located at Rajka, Medve and Komárom (1848, 1806 and 1766 river km) under the authority of the Inspectorate for Environment, Nature and Water of the North Transdanubian Region designated by the Hungarian National Monitoring Programme. Sixteen PAHs identified by the US Environmental Protection Agency (USEPA) as priority pollutants were monitored.

Concentrations of total 16 PAHs (ΣPAHs) ranged from 25 to 357 ng·L-1 with the mean value of 98.27 ± 58.48 ng·L-1. The low and medium molecular weight PAHs (2-3 and 4 ring) ranged from below method detection limit (<1) to 136 ng·L-1 while high molecular weight PAHs (5-6 ring) were present at much lower concentrations (<1-25 ng·L-1). The 2-3-ring PAHs contributed to about 64% while 4-6-ring PAHs accounted for 36% of the ΣPAHs. The dominant species are naphthalene and phenanthrene in the surface water. Concentration ratios of specific PAH compounds including anthracene/(anthracene+phenanthrene) and fluoranthene/(fluoranthene+pyrene) were calculated to evaluate the possible sources of PAH contamination. The levels of ΣPAHs determined in our study were compared with other sections of the Danube and other regions of the world.

Abstract

This research work is still considered as a theoretical reference material for transmitting the important role that thermoelectric materials play in evolving reality of our world. In this update, a brief reminder of the basics behind thermoelectric materials is provided, followed by some of the most recent developments, whether successful or not, in the attempt to create new more efficient materials for heat recovery within the coming years. One of the approaches deals with an innovative way to produce an already existing base material for thermoelectric application, whilst the other approaches describe new possibilities that were attempts to reach a higher dimensional figure of merit zT.

Abstract

Today’s vehicles are becoming more and more complex in order to meet the ever increasing safety and comfort requirements. Most people usually do not consider the car sitting in their driveway to be on the leading edge of new technology. However, for most people, the personal automobile has now become their initial exposure to new intelligent computational technologies such as fuzzy logic, neural networks, adaptive computing, voice recognition and others. This paper explores the sensory-network of electric vehicles and analyses it from a security and reliability perspective.

Abstract

This treatise was carried out with the aim of giving the reader an overview of different conceptual approaches of the competitiveness. It particularly deals with the competitiveness according to the “practical” approach, “environmental/system” approach, “capital reorganisation” approach and with the widely accepted closed definitions of competitiveness. To determine the components of competitiveness according to different aspects, to assess some empirical examinations regarding the analysis of the aforementioned aspects as well as to present the results of an own primer research are also important parts of the treatise.

Abstract

Involvement of European Union plays an important role in the areas of education and training equally. The member states are responsible for organizing and operating their education and training systems themselves. And, EU policy is aimed at supporting the efforts of member states and trying to find solutions for the common challenges which appear. In order to make our future sustainable maximally; the key to it lies in education. The highly qualified workforce is the key to development, advancement and innovation of the world. Nowadays, the competitiveness of higher education institutions has become more and more appreciated in the national economy. In recent years, the frameworks of operation of higher education systems have gone through a total transformation. The number of applying students is continuously decreasing in some European countries therefore only those institutions can “survive” this shortfall, which are able to minimize the loss of the number of students. In this process, the factors forming the competitiveness of these budgetary institutions play an important role from the point of view of survival. The more competitive a higher education institution is, the greater the chance is that the students would like to continue their studies there and thus this institution will have a greater chance for the survival in the future, compared to ones lagging behind in the competition. Aim of our treatise prepared is to present the current situation and main data of the EU higher education and we examine the performance of higher education: to what extent it fulfils the strategy for smart, sustainable and inclusive growth which is worded in the framework of Europe 2020 programme. The treatise is based on analysis of statistical data.

Abstract

Objectives. The aim of this study is to evaluate the efficacy of immediate weight-bearing versus two weeks delayed weight-bearing following anterior cruciate reconstruction.

Methods. We conducted a prospective observational study on the efficiency of immediate or delayed weight-bearing following anterior cruciate reconstruction. 30 patients undergoing anterior cruciate ligament reconstruction were included in the study. The patients in the first group were allowed the maximum endurance level of weight-bearing on the operated leg from the first postoperative day, resuming normal walking as soon as possible. Patients in group II were barely allowed the loading of the affected limb after 2 weeks postoperatively. Patient assessment was performed preoperatively, immediately after the procedure and postoperatively at 6 weeks, 3 and 6 months.

Results. The average pre- and postoperative values of the arthometric assessment show a statistically significant improvement of joint stability in both groups of patients. There were no significant differences in the development of joint mobility averages between the two groups. Following the evolution of functional test average values, there is a gradual function improvement in both groups of patients. The assessment results at 6 weeks and three months postoperatively shows that patients in the first group are significantly better in comparison with the results of patients in group II. The final evaluation showed no significant differences between the two groups of patients.

Conclusions. The final assessment revealed no statistically significant difference in reported or objectively measured function. We believe that the weight-bearing exercises and the non–weight-bearing exercises are equally effective and safe in the post-ligamentoplasty recovery.

Abstract

Leucojum vernum L. (Amaryllidaceae) is a bulbous geophyte from Central Europe known as medicinal and ornamental plant. Native population of this species can be found in the Peres Forest (parcels number 23-24) from Velyka Dobron Wildlife Reserve (Western Ukraine), monitored continuously since 2014. The aim of this study was the morphometric evaluation of the species and the chemistry analysis of the soil in which the species grow. According to our results the length of leaf sheath was the most variable parameter from the evaluated morphometric indicators (number of leaves, maximum leaf length and width, bract length, leaf sheath length, scape length, and bulb diameter). Correlations were found between maximum leaf length and scape length, but also between maximum leaf length and bract length. Soil chemistry analysis showed that the chemical properties of the soil are favorable for the studied plants. The soil pH was slightly acidic, the humus content and the supply of alkaline hydrolyzed nitrogen were high, and the amount of soluble P2O5 was moderate. Differences between the territories were found with respect to the soil agrochemical parameters.

Abstract

Flood conveyance of floodplains is significantly influenced by the riparian vegetation cover, since vegetation affects flow velocity, therefore has a considerable impact on flood height and rate and pattern of sedimentation. However, climate change promotes the spread of invasive species, and their rapid growth results in dense vegetation stands, thus they have a significant impact on floodwater hydraulics. The aims of the present study are (1) to analyse the long-term changes in land-use and vegetation density on the Lower Tisza River, (2) to evaluate the role of the invasive Amorpha fruticosa in increasing vegetation density, and (3) to model the effect of dense floodplain vegetation on flood level and flood conveyance. Long-term (1784-2017) changes of land-use suggest that in natural conditions the study area was occupied by wetlands (92%), thus water covered the area for almost the whole year. In the 19th century, after levee constructions the wetlands were replaced by meadows and pastures (94%), then by the end of the 20th century planted and riparian forests replaced these land-covers. As a result, the mean roughness (0.14) of the floodplain has increased threefold until the early 21st century. Today forests are invaded by Amorpha fruticosa, which increases the vegetation density by 3% in riparian forests, by 23% in forest plantations, and by up to 100% in abandoned pastures and a rable lands. According to the results of HEC-RAS (Hydrologic Engineering Center’s River Analysis System) and CES (Conveyance Estimation System) models, if floodplain vegetation was managed and Amorpha fruticosa was cleared from the floodplain, peak flood level would decrease by 15 cm. Due to dense vegetation, the flood conveyance decreased by 4-6%, and the presence of Amorpha fruticosa reduced the flood flow velocities by 0.014-0.016 m/s. Accordingly, clearance of the floodplain from Amorpha fruticosa would have positive effects on flood protection, since peak flood stages would decrease and flood waves would shorten.

Abstract

The Corncrake is a strictly protected species in Hungary and a qualifying species of many Natura 2000 sites. Despite its Least concern global conservation status, it receives much attention and was elected as “Bird of the Year” by MME BirdLife Hungary in 2016. In this paper, we estimate its population trends and analyse the suitability of the protected area system and agri-environment schemes for the species. We compiled information on major threatening factors and conservation measures applied for the species. We reviewed international publications on the ecology and conservation management of the species to extract information for practical conservation. We estimated that 500–2000 pairs of Corncrakes breed in Hungary. Although their breeding sites are well covered by protected areas, Natura 2000 sites (42%) and High Nature Value Areas (67%), their population has declined by 55% over the last 20 years. We found that most of the major threatening factors are addressed by conservation management, and appropriate measures are applied in most cases. Recent research findings and recommendations by the BirdLife International Corncrake Conservation Team suggest that mowing of grasslands around nesting places should be delayed until 1–15 August either in the entire field or at least on 2 hectares around nests. Prescriptions of agri-environment schemes should also be adjusted to the above requirements and more farmers should be encouraged to enrol in Corncrake conservation programmes. We strongly suggest that more emphasis should be devoted to combat important threats for the most important breeding sites such as aridification and flooding.

Abstract

Super duplex stainless steels are used in increasingly more areas. The machinability of duplex stainless steels is generally poor. We performed dry turning tests on G X2CrNiMoCuN 26-6-3-3 casted superduplex steel, using two different PVD coated cutting inserts. One of them was coated with TiAlN and other with TiAlSiN. Strong burr and built-up edge formation were observed during our machining experiments; these damaged the edges of the tools. The shortened tests did not show significant difference betwen the effect of the coatings.